7th Grade Math

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Surface Area

PART A BCDEF

Multi-Part

Lesson 2

Addresses

GLE 0706.1.3, GLE 0706.1.8.

580 Volume and Surface Area

Nets of Three-Dimensional Figures

Nets are two-dimensional patterns of three-dimensional figures. When

you construct a net, you are decomposing the three-dimensional figure

into separate figures. You can use a net to find the surface area of

three-dimensional figures such as prisms, pyramids, and cylinders.

Use an empty cereal box. Measure and record the

length, width, and height of the box.

Label the top and bottom faces using a green marker.

Label the front and back faces using a blue marker and

label the left and right faces using a red marker.

Carefully cut along three edges of the top face and

then cut down each vertical edge.

left bottom right

top

back

front

the Results

1. Name the shape(s) that make up the net.


2. What do you notice about the top and bottom faces, the left and
   right faces, and the front and back faces?


3. Explain how you could find the total area of the rectangles.


4. MAKE A CONJECTURE Write the formula for the surface area of the
   box using the net. Justify your answer.

Main Idea

Find the surface area

of prisms and cylinders

using models and nets.

Vocabulary

net

V

n

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