The area of the base of a prism is 21 cm squared. The perimeter of the base is 20 cm. The height of the prism is 8 cm. What is the surface are of the prism?.

SA=ph+2b is the right formula for this question.

p = perimeter h = height b=base

Since the base area of this prism is 21cm^2 we can multiply by 2.

21*2=42cm^2

And we know the perimeter of the base is 20 and the height is 8 we just multiply.

20*8 = 160cm^2

Now we add

160+42 = 202cm^2 is the surface area of this prism.