Question

As you already know, a cube has six square faces. Suppose if each of those faces is 3 inches by 3 inches, then the area of each face is 3x3 = 9 square inches. And since there are six of them, the total surface area is 9 + 9 + 9 + 9 + 9 + 9 = 54 square inches. To find the surface area of any shape, you can follow the process described below: 1. Draw a net of the rectangular prism 2. Calculate the area of each face. 3. Add up the area of all the faces.

Answer 1

1. A draw of a rectangular prism is shown below:

where h is the height, w is the width and le the length of the rectangular prims.

2. The area of the face with sides w and h is w·h. There are two faces with these dimensions.

The area of the face with sides h and l is h·l. There are two faces with these dimensions.

The area of the face with sides w and l is w·l. There are two faces with these dimensions.

3.

Then, the total surface area of the prism is:

A = 2w·h + 2h·l + 2w·l