For each of the following, the Surface Area is given. Calculate the missing dimension.

Question

This is a rectangular prism with the width missing. The height seems to be 20 cm. The length I guess is 34 cm, and the Surface Area is 6020cm square. How do I find the missing width? I checked in the back of the book for the answer and it said 43.1. I have no clue how they came up with that.

Also the formula my teacher gave me to find the surface area of this dimension is....

SA = 2lw + 2lh+ 2wh.

I just don't get how to find the missing dimension. Please Help.

Answer 1

Just plug in your given values into the equation

6020 = 2(34)w + 2(34)(20) + 2(w)(20)
6020 = 68w + 1360 + 40w
4660 = 108w
w = 43.148 , your answer

Answer 2

Thanks a lot Reiny! I love your help.

Answer 3

your are welcome

May I suggest you use a "nickname" instead of "anonymous"
If you use the same computer each time you will not have to type it each time.