Using a ruler, measure the dimensions of a tissue box that is in the shape of a rectangular prism.

Question

Using a ruler, measure the dimensions of a tissue box that is in the shape of a rectangular prism. Assume that the entire tissue box is made of cardboard. How many square inches of cardboard were used to create the tissue box? (Ignore any overlap in the cardboard.)

Answer 1

When finding square inches, you are looking for the area.  A rectangular prism is a 3D figure composed of flat rectangles.  To find the area of this figure, take the area of each rectangular face. Then, add up those areas. Keep in mind that NOT all rectangular faces are sized the same. This means that the length and width of one rectangle may NOT be the same as the length and width of another rectangle.

 

 

First, is to measure the length and width of each rectangular face.

Second, is find the areas of each face.

Last, is to add up those areas.

 

 

Use this formula for finding the area.

Area = Length × Width