Question

Find the value of Z. A)7 B)9 C)11 D)12

Answer 1

As per the isosceles triangle theorem, if the two base angles are congruent then the legs are also congruent, so we must set the two legs equal to each other:

2z - 15 = 9

Add 15 to both sides:

15 - 15 = 0
15 + 9 = 24

Divide 2 from each side:

2z = 24

2z/2 = z

24/2 = 12

z = 12

Hence, the answer would be D: z = 12

Answer 2

$2z-15=9\\2z=24\\z=12$