.. _angle:

angle
=====

.. index:: planes, lines, angles

.. image:: angle.png
   :align: right
   :width: 300px

..

  A *plane angle* is the inclination to one another of two lines in a plane which meet one another and do not lie in a straight line.

  And when the lines containing the angle are straight, the angle is called *rectilineal*.

  -- Euclid

Angles arise out of the relation of intersecting lines

.. toctree::

   acute/index.rst
   obtuse/index.rst
   right/index.rst