EXAMPLE 1 Drawing a Net

SOLUTION

METHOD 1

Draw a net of the triangular prism.

Draw one base with a rectangleadjacent to each side. Draw the other base adjacent to one of the rectangles.

EXAMPLE 1 Drawing a Net

METHOD 2

For the rectangular faces, draw adjacent rectangles. Draw thebases on opposite sides of one rectangle.

EXAMPLE 2 Using a Net to Find Surface Area

Storage Chest

You are painting a storage chest with the given dimensions. Find the surface area to be painted.

EXAMPLE 2

SOLUTION

Using a Net to Find Surface Area

Draw a net of the chest. The area of each square face is 15 in. 15 in. = 225 in.2 The area of each rectangular face is 30 in. 15 in. = 450 in.2

There are two square faces and four rectangular faces, so the surface area is 2 225 in.2 + 4 450 in.2 = 2250 in.2

EXAMPLE 2

ANSWER

The surface area of the storage chest is 2250 square inches.

Using a Net to Find Surface Area

EXAMPLE 3 Using a Formula to Find Surface Area

S = 2B + Ph12= 2( 10 12) + (13 + 13 + 10)15

= 660

Find the surface area of the triangular prism.

ANSWER

The surface area of the prism is 660 square centimeters.

EXAMPLE 4 Finding the Surface Area of a Cylinder

Packaging

SOLUTION

The radius is one half the diameter, so r = 4 cm.

Find the surface area of the canof sloppy joe sauce.

S = 2πr2+ 2πrh= 2π(4)2 + 2π(4)(10.7)≈ 369.45

Write formula for surface area.

Substitute 4 for r and 10.7 for h.

Evaluate using a calculator.

ANSWER

The surface area of the can is about 369 square centimeters.

GUIDED PRACTICE for Examples 1, 2, 3, and 4

Draw a net of the solid. Then find the surface area. Round to the nearest tenth. Check your answer for reasonableness.1.

ANSWER

222 ft2

GUIDED PRACTICE for Examples 1, 2, 3, and 4

ANSWER

384 m2

GUIDED PRACTICE for Examples 1, 2, 3, and 4

ANSWER

1407.4 in.2