Acute triangle
From AoPSWiki
An acute triangle is a triangle in which each angle is an acute angle. Any triangle which is not acute is either a right triangle or an obtuse triangle.
Acute triangles can also be defined in different ways:
- A triangle is acute if and only if each of its altitudes lies entirely in the triangle's interior.
- A triangle with sides of length
and 
is acute if and only if 
, 
and 
. This is known as the Pythagorean Inequality.
This article is a stub. Help us out by expanding it.
