EXAMPLE 1 Drawing a Net Draw a net of the triangular prism. SOLUTION METHOD 1 Draw one base with a rectangle adjacent 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 the bases 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 Using a Net to Find Surface Area SOLUTION 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 Using a Net to Find Surface Area ANSWER The surface area of the storage chest is 2250 square inches.
EXAMPLE 3 Using a Formula to Find Surface Area Find the surface area of the triangular prism. S = 2B + Ph 1 2 = 2( 10 12) + (13 + 13 + 10)15 = 660 ANSWER The surface area of the prism is 660 square centimeters.
Finding the Surface Area of a Cylinder EXAMPLE 4 Finding the Surface Area of a Cylinder Packaging Find the surface area of the can of sloppy joe sauce. SOLUTION The radius is one half the diameter, so r = 4 cm. S = 2πr2+ 2πrh Write formula for surface area. = 2π(4)2 + 2π(4)(10.7) Substitute 4 for r and 10.7 for h. ≈ 369.45 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