Question

An isosceles triangle has an interior angle of 26 degrees. Which of the following is a possible degree measure for one of the other interior angles of the triangle?
a) 52 degrees
b) 64 degrees
c) 78 degrees
d) 104 degrees
e) 128 degrees

Answer 1

The answer should be c). The sum of angles for a triangle is 180 degrees. Since this is an isosceles triangle, it must have two equivalent angles. Therefore 180-26 = 154 degrees. When we divide 154 by 2, we get 77 degrees. So the possible degree measure is 78.