In order to calculate surface area, you need to find each individual rectangle. Four sides of the rectangle will be your length times height, so 14*4 or 56 cm. As for the other two sides, they would be height times width, so 4*6 or 24 cm. The four sides would add up to 224 cm and the other two would be 48 total. When you add all six sides together, you get 272 cm.
