Question

8.

(3 Points) Find the value of x, then find the measure of angle Y.
X
73°
(4x + 9)
Z

Answer 1

x = 16

m∠Y = 34°

Explanation:

Triangle XYZ is an isosceles triangle so, the angles ∠X and ∠Y are equal in measurement.

We can write the following equation to find the value of x:

4x + 9 = 73

Subtract 9 from both sides.

4x = 64

Divide both sides with 4.

x = 16

The sum of interior angles in a triangle is equal to 180°.

m∠X + m∠Y + m∠Z = 180°

73 + 73 + m∠Y = 180°

• Add like terms.

146 + m∠Y = 180°

• Subtract 146 from both sides.

m∠Y = 34°