When adding make sure you add 4 sides worth of calculations. You have to consider the left and right side (for length) and front and back for the width.
The solution for this problem is:
Side 1 (8+36+8)
+
Side 2 (8+48+8)
+
Side 3 (8+36+8)
+
Side 4 (8+48+8)
= 232