Which David should win American Idol?

David Archuleta
David Cook

View Results

Special Names for Sides and Angles

Legs, base, vertex angle, and base angles. In an isosceles triangle, the two equal sides are called legs, and the third side is called the base. The angle formed by the two equal sides is called the vertex angle. The other two angles are called base angles (Figure 1 ).





Figure 1

Parts of an isosceles triangle.


In a right triangle, the side opposite the right angle is called the hypotenuse, and the other two sides are called legs (Figure 2 ).





Figure 2

Parts of a right triangle.


Cite this article

cover
Get Up to Speed on the Math You Really Need!
Basic math for use in the real world.
Get Math You Can Really Use — Every Day!
Feeling Trapped by Trapezoids?
Get Help with Geometry Now!