Answer:
x = 15
Step-by-step explanation:
Corresponding sides of similar shapes are proportional to each other. Thus:
(10 + 2)/10 = (x + 3)/x
12/10 = (x + 3)/x
Cross multiply
12*x = (x + 3)*10
12x = 10x + 30
12x - 10x = 30
2x = 30
x = 30/2
