right triangle
Further, of trilateral figures,
a right-angled triangle is that which has a right angle,
an obtuse-angled triangle that which has an obtuse angle,
and an acute-angled triangle that which has its three angles acute.
—Euclid
Further, of trilateral figures,
a right-angled triangle is that which has a right angle,
an obtuse-angled triangle that which has an obtuse angle,
and an acute-angled triangle that which has its three angles acute.
—Euclid