If you have a coin made of the densest element that weighs 124.05 g, and has a thickness of 4.00 mm, what is the diameter (in cm) of the coin?

3.00

Step-by-step explanation:

To find the surface area you will need to find the area of all 5 surfaces (faces) on the prism.  On a triangular prism there are 2 triangular faces and 3 rectangular faces.  All 3 rectangular faces are the same and the 2 triangular faces are also the same.

To find the area of the triangular faces, you will use the formula for finding the area of a triangle:

A = 1/2bh
     1/2 x 10 x 8.7
A = 43.5 in^2 

To find the area of the rectangular faces, you will use the formula for finding the area of a rectangle:

A = bh
    10 x 3
A = 30 in ^2

30 + 30 + 30 + 43.5 + 43.5 = 177

The minimum amount of wrapping paper needed for the gift is 177 square inches.