The surface area is 870 cm².
Since the base is a regular quadrilateral, each side is the same; dividing the perimeter by 4 will give us the side length:
60/4 = 15
To find the area, we square the side length:
15² = 225
There are two bases, so the area of these is 2(225) = 450
There are 4 lateral faces, so the lateral area is 4(105) = 420
Together, this gives us a total surface area of 870.
