Question

Question below, I already did half of it but I can't get the perimeter?

a= 18
b= 3
c= 42

Answer 1

Answer: blue triangle: 53 - red triangle: 17

Explanation:

12+2+7\left(3\right)+7+5\left(3\right)-4

12+2+21+7+5\left(3\right)-4

12+2+21+7+15-4

53

3+3+6-5+3+7