Answer:
a. x = 14
b. Perimeter = 77
Step-by-step explanation:
a. Based on the Triangle Proportionality Theorem:
Cross multiply
Add 2 to both sides
Divide both sides by 2
x = 14
b. Perimeter of ∆QRS = RQ + QS + RS = (2x - 2) + 13 + 17 + (21 - 7) + 7
Plug in the value of x
= (2(14) - 2) + 13 + 17 + 14 + 7
= 26 + 13 + 17 + 14 + 7
= 77