Hands-on math!

Isosceles triangle

An isosceles triangle is a triangle that has 2 sides the same length and 2 angles the same measure. This triangle is isosceles.
For example, if you have an isosceles triangle and has one angle that is 100 degrees, what are the other 2 angles?
Well, the other 2 angles sum to 80 degrees (180 - 100), and both of the other 2 angles are the same, so the sum of the other 2 identical angles is 80 degrees, so each of the other angles must be 40 degrees!

Use the space below to draw this triangle!

To learn more about triangles, see the triangle notes.

Now here are a couple of problems for you:

1). What is the 3rd angle of an isosceles triangle whose other 2 angles are 50 degrees each?

Angle = ______ degrees.
  2). One angle of an isosceles triangle is 20 degrees. What are the 2 possible values of the other 2 angles?

______ and ______ degrees or

______ and ______ degrees.