The box has volume
11 in × 3 in × x in = 33x in³
and surface area
2 (11 in × 3 in + 11 in × x in + 3 in × x in) = (66 + 28x) in²
The volume and area have the same value if
33x = 66 + 28x
Solve this equation for x :
33x - 28x = 66
5x = 66
x = 66/5 = 13.2
