.. _right angle:

right angle
===========

.. index:: angles

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

..

   When a straight line set up on a straight line makes the adjacent angles
   equal to one another, each of the equal angles is *right*, and the straight
   line standing on the other is called a *perpendicular* to that on which it
   stands.

   -- Euclid

Perpendicular