Question

What is the missing length of a rectangular prism where the height and width are both 9 cm and the surface area is 432 cm squared?
Answered by GPT 3.5
To find the missing length, we need to first find the total surface area of the rectangular prism.

Surface Area of a Rectangular Prism = 2lw + 2lh + 2wh

Given that the height and width are both 9 cm, we can plug in the known values:

432 = 2(l)(9) + 2(l)(9) + 2(9)(9)
432 = 18l + 18l + 162
432 = 36l + 162
270 = 36l
l = 270 / 36
l = 7.5

Therefore, the missing length of the rectangular prism is 7.5 cm.