Today’s ACT question of the day is almost too easy to explain.  We are given an isosceles triangle, drawn to scale, and the measure of the third angle (the one without a corresponding angle): 22 degrees.

Isosceles triangles have two congruent angles and two congruent sides.  There are 180 degrees inside a triangle.  If you keep those two ideas in mind, you will have this problem solved before I can even finish explaining.

First, let’s find out how many degrees make up the two congruent angles by getting rid of the third angle:

180 – 22 = 158 degrees

Next, let’s separate that into two parts to find the measure of each of the two congruent angles:

158 / 2 = 79 degrees

Done!  Keep your triangle basics in mind and you can breeze through problems like this one in order to save your time for more complex questions.