— GEOMETOR • elements

G.180 proportional magnitudes

Let magnitudes which have the:term:same ratio <G.176> be called:term:**proportional** <proportional>.

G.183 equal magnitudes ratio

Equal magnitudes have to the same the same ratio, as also has the same to equal magnitudes.

G.190 number magnitudes proportional

If any number of magnitudes be proportional, as one of the antecedents is to one of the consequents, so will all the antecedents be to all the consequents.

G.195 magnitudes proportional proportional

If four magnitudes be proportional, they is proportional alternately.

G.198 magnitudes proportional componendo

If magnitudes be proportional componendo, they is proportional separando.

G.199 magnitudes proportional separando

If magnitudes be proportional separando, they is proportional componendo.

G.201 whole whole part

If, as a whole is to a whole, so is a part subtracted to a part subtracted, the remainder is to the remainder as whole to whole.

If a first magnitude have to a second the same ratio as a third has to a fourth, and also a fifth have to the second the same ratio as a sixth to the fourth, the first and fifth added together will have to the second the same ratio as the third and sixth have to the fourth.

G.208 magnitudes proportional greatest

If four magnitudes be proportional, the greatest and the least are greater than the remaining two.

G.213 equiangular triangles sides

In equiangular triangles the sides about the equal angles are proportional, and those are corresponding sides which subtend the equal angles.

G.214 triangles sides proportional

If two triangles have their sides proportional, the triangles is equiangular and will have those angles equal which the corresponding sides subtend.

G.215 triangles angle equal

If two triangles have one angle equal to one angle and the sides about the equal angles proportional, the triangles is equiangular and will have those angles equal which the corresponding sides subtend.

G.216 triangles angle equal

If two triangles have one angle equal to one angle, the sides about other angles proportional, and the remaining angles either both less or both not less than a right angle, the triangles is equiangular and will have those angles equal, the sides about which are proportional.

G.217 similar rectilineal figures

Similar polygons are such as have their:term:angles <G.22> severally equal and the sides about the equal angles:term:proportional <G.180>.

G.218 right angled triangle

If in a right-angled triangle a perpendicular be drawn from the right angle to the base, the triangles adjoining the perpendicular are similar both to the whole and to one another.

G.221 third proportional

To two given segments to find a third proportional.

G.222 fourth proportional

To three given segments to find a fourth proportional.

G.223 mean proportional

To two given segments to find a mean proportional.

G.227 segments proportional rectangle

If four segments be proportional, the rectangle contained by the extremes is equal to the rectangle contained by the means; and, if the rectangle contained by the extremes equals the rectangle contained by the means, the four segments is proportional.

G.228 segments proportional rectangle

If three segments be proportional, the rectangle contained by the extremes is equal to the square on the mean; and, if the rectangle contained by the extremes equals the square on the mean, the three segments is proportional.

G.229 describe on a given segment a rectilinear figure

Describe on a given segment a rectilinear figure similar and similarly situated to a given rectilinear figure.

G.230 duplicate ratio

When three magnitudes are:term:proportional <G.180>, the first is said to have to the third the:term:**duplicate ratio** <duplicate-ratio> of that which it has to the second.

G.231 similar triangles duplicate

Similar triangles are to one another in the duplicate ratio of the corresponding sides.

G.232 similar polygons divided

Similar polygons are divided into similar triangles, and into triangles equal in multitude and in the same ratio as the wholes, and the polygon has to the polygon a ratio duplicate of that which the corresponding side has to the corresponding side.

G.233 figures similar polygon

Figures which are similar to the same polygon are also similar to one another.

G.234 segments proportional polygons

If four segments be proportional, the polygons similar and similarly described upon them is proportional; and, if the polygons similar and similarly described upon them be proportional, the segments will themselves also be proportional.

G.236 parallelogram parallelograms diameter

In any parallelogram the parallelograms about the diameter are similar both to the whole and to one another.

G.237 construct one and the same figure similar to

Construct one and the same figure similar to a given polygon and equal to another given polygon.

G.244 right angled triangles

In right-angled triangles the figure on the side subtending the right angle is equal to the similar and similarly described figures on the sides containing the right angle.

G.245 triangles sides proportional

If two triangles having two sides proportional to two sides be placed together at one angle so that their corresponding sides are also parallel, the remaining sides of the triangles is in a segment.

G.263 proportional numbers

Numbers are:term:**proportional** <G.180> when the first is the:term:same multiple <G.256>, or the:term:same part <G.253>, or the:term:same parts <G.254>, of the second that the third is of the fourth.

G.266 numbers proportional proportional

If four numbers be proportional, they is proportional alternately.

G.273 numbers proportional number

If four numbers be proportional, the number produced from the first and fourth will equals the number produced from the second and third; and, if the number produced from the first and fourth equals that produced from the second and third, the four numbers is proportional.

G.278 numbers prime number

If two numbers be prime to any number, their product also is prime to the same.

G.296 there many numbers

If there be as many numbers as we please in continued proportion, and the extremes of them be prime to one another, the numbers are the least of those which have the same ratio with them.

G.297 find numbers in continued proportion

Find numbers in continued proportion, as many as may be prescribed, and the least that are in a given ratio.

G.298 many numbers please

If as many numbers as we please in continued proportion be the least of those which have the same ratio with them, the extremes of them are prime to one another.

G.299 many ratios please

Given as many ratios as we please in least numbers, to find numbers in continued proportion which are the least in the given ratios.

G.303 there many numbers

If there be as many numbers as we please in continued proportion, and the first do not measure the second, neither will any other measure any other.

G.304 there many numbers

If there be as many numbers as we please in continued proportion, and the first measure the last, it will measure the second also.

G.305 numbers there fall

If between two numbers there fall numbers in continued proportion with them, then, however many numbers fall between them in continued proportion, so many will also fall in continued proportion between the numbers which have the same ratio with the original numbers.

G.306 numbers prime numbers

If two numbers be prime to one another, and numbers fall between them in continued proportion, then, however many numbers fall between them in continued proportion, so many will also fall between each of them and an unit in continued proportion.

G.307 numbers fall numbers

If numbers fall between each of two numbers and an unit in continued proportion, however many numbers fall between each of them and an unit in continued proportion, so many also will fall between the numbers themselves in continued proportion.

G.309 square numbers there

Between two square numbers there is one mean proportional number, and the square has to the square the ratio duplicate of that which the side has to the side.

G.310 triplicate ratio

When four magnitudes are < continuously >:term:proportional <G.180>, the first is said to have to the fourth the:term:**triplicate ratio** <triplicate-ratio> of that which it has to the second, and so on continually, whatever be the proportion.

G.312 cube numbers there

Between two cube numbers there are two mean proportional numbers, and the cube has to the cube the ratio triplicate of that which the side has to the side.

G.313 there many numbers

If there be as many numbers as we please in continued proportion, and each by multiplying itself make some number, the products is proportional; and, if the original numbers by multiplying the products make certain numbers, the latter is proportional.

G.314 square measure square

If a square measure a square, the side will also measure the side; and, if the side measure the side, the square will also measure the square.

G.315 cube number measure

If a cube number measure a cube number, the side will also measure the side; and, if the side measure the side, the cube will also measure the cube.

G.318 similar plane and solid numbers

Similar plane and solid numbers are those which have their sides:term:proportional <G.180>.

G.319 similar plane numbers

Between two similar plane numbers there is one mean proportional number; and the plane number has to the plane number the ratio duplicate of that which the corresponding side has to the corresponding side.

G.321 similar solid numbers

Between two similar solid numbers there fall two mean proportional numbers; and the solid number has to the similar solid number the ratio triplicate of that which the corresponding side has to the corresponding side.

G.322 mean proportional number

If one mean proportional number fall between two numbers, the numbers is similar plane numbers.

G.323 mean proportional numbers

If two mean proportional numbers fall between two numbers, the numbers are similar solid numbers.

G.324 numbers continued proportion

If three numbers be in continued proportion, and the first be square, the third is square.

G.325 numbers continued proportion

If four numbers be in continued proportion, and the first be cube, the fourth is cube.

G.326 numbers ratio square

If two numbers have to one another the ratio which a square number has to a square number, and the first be square, the second is square.

G.327 numbers ratio cube

If two numbers have to one another the ratio which a cube number has to a cube number, and the first be cube, the second is cube.

G.328 similar plane numbers

Similar plane numbers have to one another the ratio which a square number has to a square number.

G.329 similar solid numbers

Similar solid numbers have to one another the ratio which a cube number has to a cube number.

G.330 similar plane numbers

If two similar plane numbers by multiplying one another make some number, the product is square.

G.331 numbers multiplying make

If two numbers by multiplying one another make a square number, they are similar plane numbers.

G.332 cube number multiplying

If a cube number by multiplying itself make some number, the product is cube.

G.333 cube number multiplying

If a cube number by multiplying a cube number make some number, the product is cube.

G.334 cube number multiplying

If a cube number by multiplying any number make a cube number, the multiplied number is cube.

G.335 number multiplying itself

If a number by multiplying itself make a cube number, it will itself also be cube.

G.337 many numbers please

If as many numbers as we please beginning from an unit be in continued proportion, the third from the unit is square, as will also those which successively leave out one; the fourth is cube, as will also all those which leave out two; and the seventh is at once cube and square, as will also those which leave out five.

G.338 many numbers please

If as many numbers as we please beginning from an unit be in continued proportion, and the number after the unit be square, all the rest is square. And, if the number after the unit be cube, all the rest is cube.

G.339 many numbers please

If as many numbers as we please beginning from an unit be in continued proportion, and the number after the unit be not square, neither will any other be square except the third from the unit and all those which leave out one. And, if the number after the unit be not cube, neither will any other be cube except the fourth from the unit and all those which leave out two.

G.340 many numbers please

If as many numbers as we please beginning from an unit be in continued proportion, the less measures the greater according to some one of the numbers which have place among the proportional numbers.

G.342 many numbers please

If as many numbers as we please beginning from an unit be in continued proportion, by however many prime numbers the last is measured, the next to the unit is measured by the same.

G.343 many numbers please

If as many numbers as we please beginning from an unit be in continued proportion, and the number after the unit be prime, the greatest will not be measured by any except those which have a place among the proportional numbers.

G.345 numbers continued proportion

If three numbers in continued proportion be the least of those which have the same ratio with them, any two whatever added together is prime to the remaining number.

G.347 there many numbers

If there be as many numbers as we please in continued proportion, and the extremes of them be prime to one another, the last will not be to any other number as the first to the second.

G.348 numbers investigate whether

Given two numbers, to investigate whether it is possible to find a third proportional to them.

G.349 numbers investigate possible

Given three numbers, to investigate when it is possible to find a fourth proportional to them.

G.364 numbers continually doubled

Each of the numbers which are continually doubled beginning from a dyad is even-times even only.

G.368 many numbers please

If as many numbers as we please be in continued proportion, and there be subtracted from the second and the last numbers equal to the first, then, as the excess of the second is to the first, so will the excess of the last be to all those before it.

G.370 many numbers please

If as many numbers as we please beginning from an unit be set out continuously in double proportion, until the sum of all becomes prime, and if the sum multiplied into the last make some number, the product is perfect.

G.377 magnitudes ratio number

If two magnitudes have to one another the ratio which a number has to a number, the magnitudes is commensurable.

G.381 squares segments commensurable

The squares on segments commensurable in length have to one another the ratio which a square number has to a square number; and squares which have to one another the ratio which a square number has to a square number will also have their sides commensurable in length. But the squares on segments incommensurable in length have not to one another the ratio which a square number has to a square number; and squares which have not to one another the ratio which a square number has to a square number will not have their sides commensurable in length either.

G.382 magnitudes proportional commensurable

If four magnitudes be proportional, and the first be commensurable with the second, the third is commensurable with the fourth; and, if the first be incommensurable with the second, the third is incommensurable with the fourth.

G.383 find two segments incommensurable

Find two segments incommensurable, the one in length only, and the other in square also, with an assigned segment.

G.386 segments proportional square

If four segments be proportional, and the square on the first be greater than the square on the second by the square on a segment commensurable with the first, the square on the third is greater than the square on the fourth by the square on a segment commensurable with the third. And, if the square on the first be greater than the square on the second by the square on a segment incommensurable with the first, the square on the third is greater than the square on the fourth by the square on a segment incommensurable with the third.

G.401 find medial segments commensurable in square only which

Find medial segments commensurable in square only which contain a rational rectangle.

G.402 find medial segments commensurable in square only which

Find medial segments commensurable in square only which contain a medial rectangle.

G.434 area contained rational

If an area be contained by a rational segment and the first binomial, the “side” of the area is the irrational segment which is called binomial.

G.435 area contained rational

If an area be contained by a rational segment and the second binomial, the “side” of the area is the irrational segment which is called a first bimedial.

G.440 square binomial segment

The square on the binomial segment applied to a rational segment produces as breadth the first binomial.

G.477 area contained rational

If an area be contained by a rational segment and a first apotome, the “side” of the area is an apotome.

G.478 area contained rational

If an area be contained by a rational segment and a second apotome, the “side” of the area is a first apotome of a medial segment.

G.479 area contained rational

If an area be contained by a rational segment and a third apotome, the “side” of the area is a second apotome of a medial segment.

G.480 area contained rational

If an area be contained by a rational segment and a fourth apotome, the “side” of the area is minor.

G.483 square apotome applied

The square on an apotome applied to a rational segment produces as breadth a first apotome.

G.484 square apotome medial

The square on a first apotome of a medial segment applied to a rational segment produces as breadth a second apotome.

G.485 square apotome medial

The square on a second apotome of a medial segment applied to a rational segment produces as breadth a third apotome.

G.486 square minor segment

The square on a minor segment applied to a rational segment produces as breadth a fourth apotome.

G.488 square segment produces

The square on the segment which produces with a medial area a medial whole, if applied to a rational segment, produces as breadth a sixth apotome.

G.498 square rational segment

The square on a rational segment applied to the binomial segment produces as breadth an apotome the terms of which are commensurable with the terms of the binomial and moreover in the same ratio; and further the apotome so arising will have the same order as the binomial segment.

G.536 describe on a given segment a parallelepipedal solid

Describe on a given segment a parallelepipedal solid similar and similarly situated to a given parallelepipedal solid.

G.543 similar parallelepipedal solids

Similar parallelepipedal solids are to one another in the triplicate ratio of their corresponding sides.

G.546 segments proportional parallelepipedal

If three segments be proportional, the parallelepipedal solid formed out of the three is equal to the parallelepipedal solid on the mean which is equilateral, but equiangular with the aforesaid solid.

G.547 segments proportional parallelepipedal

If four segments be proportional, the parallelepipedal solids on them which are similar and similarly described is proportional; and, if the parallelepipedal solids on them which are similar and similarly described be proportional, the segments will themselves also be proportional.

Posts tagged 'proportional'