Question

find the value of x.
x + 3
12
a. -12
b. -9
c. 15
d. 9

Explanation:

Step1: Assume equal - length sides

Since the two marked angles are equal, the sides opposite them are equal. So we set up the equation $x + 3=12$.

Step2: Solve for x

Subtract 3 from both sides of the equation: $x=12 - 3$.

Answer:

D. 9