IXL | Surface area of cubes and rectangular prisms

A cube is shown below.

Which diagram is a net for the cube?

What is the surface area of the cube?

square centimeters

ref_doc_title.

Learn with an example

question

A rectangular prism is shown below.

Which diagram is a net for this prism?

What is the surface area of the rectangular prism?

square centimeters

key idea

A net shows all the faces of a three-dimensional figure.

A rectangular prism has six rectangular faces. Its surface area is the sum of the areas of all six faces.

solution

Six faces make up the rectangular prism:

two rectangular faces with a length of 15 centimeters and a width of 8 centimeters
two rectangular faces with a length of 19 centimeters and a width of 15 centimeters
two rectangular faces with a length of 19 centimeters and a width of 8 centimeters

This is a net for the prism. It shows all of the faces and, when folded up, will form the prism.

To find the surface area, add up the areas of all six faces.

There are two rectangular faces with a length of 15 centimeters and a width of 8 centimeters. Find the area of one of them.

(

)

120

square centimeters

There are two rectangular faces with a length of 19 centimeters and a width of 15 centimeters. Find the area of one of them.

(

)

285

square centimeters

There are two rectangular faces with a length of 19 centimeters and a width of 8 centimeters. Find the area of one of them.

(

)

152

square centimeters

Finally, find the sum of the areas of all six rectangular faces.

(

120

)

(

285

)

(

152

)

240

570

304

1,114

The surface area of the rectangular prism is 1,114 square

centimeters.

Looking for more? Try this:

Lesson: What is surface area?

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Teacher tools

Work it out

Not feeling ready yet? These can help:

FF.3Nets of three-dimensional figures

GG.2Area of rectangles and squares

H.1Add and subtract decimal numbers

I.3Multiply decimals

Lesson: What is surface area?

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