Question

Triangle XYZ is an isosceles triangle.

XY = YZ
mY = 42°
What is mZZ?
Y
42°
N

Answer 1

If triangle XYZ is isosceles, then the two sides (XY and YZ) are congruent in addition to the two base angles.

Angle Y (the one at the top of the triangle) = 42 degrees

Angles X and Z are congruent because of the properties of an isosceles triangle. Let's call both angle measures "x" in our equation.

x + x + 42 = 180

2x + 42 = 180

2x = 138

x = 69

Answer: The measure of Angle Z is 69 degrees.

Hope this helps!