IXL | Lateral area of pyramids | 7th grade math

or

A triangular pyramid is shown below. Its base is an equilateral triangle with a side length of

12

centimeters

.

Which diagram is a net for the pyramid?

What is the lateral area of the triangular pyramid?

square centimeters

ref_doc_title.

or

Learn with an example

question

A rectangular pyramid is shown below.

Which diagram is a net for the pyramid?

What is the lateral area of the rectangular pyramid?

square millimeters

key idea

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

A rectangular pyramid has a rectangular base and four triangular lateral faces. Its lateral area is the sum of the areas of the lateral faces.

solution

Five faces make up the rectangular pyramid:

one square base with a side length of
10
millimeters
four triangular lateral faces, each with a base of
10
millimeters
and a height of
6
millimeters

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

To find the lateral area of the pyramid, add up the areas of the four triangular lateral faces.

All four triangular faces have a base of

10

millimeters

and a height of

6

millimeters

.

Find the area of one of them.

A

=

1

2

b

h

A

=

1

2

(

10

)

(

6

)

A

=

1

2

(

60

)

A

=

30

square millimeters

Finally, multiply

30

square millimeters

by 4.

4

(

30

)

=

120

The lateral area of the rectangular pyramid is

120

square millimeters

.

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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

GG.6Area of triangles