Round off the decimals to a sensible number.
So 3.7 would be 4 and 10.2 would be 10.
In this case, it would be (2 × 4 + 8) × 10 which is 160.
$15 + $32.50 + 8% = $51.30
15 + 32.50 = 47.50
8% × 47.50 = 3.80
47.50 + 3.80 = 51.30
Multiply both sides by 3 to get:
3r = sqrt(A)
Square both sides:
9r^2 = A
X = 3
y = -3
You will see this using any graphing tool at your disposal.