7th Grade Math

Surface Area of a Pyramid

Find the total surface area of the pyramid.

9 in.

4 in.

4 in.

Round to the nearest tenth.

S.A. = B + _^1

2

P Surface area of a pyramid

S.A. = 16 + _^1

2

( 16 · 9 ) B = 4 · 4 , P = 4 · 4 or 16,  = 9

S.A. = 88 Simplify.

The surface area is 88 square inches.

Find the total surface area of the pyramid

16 m

20 m

16 m 16 m

with a base area of 111 square meters.

S.A. = B + _^1

2

P Surface area of a pyramid

S.A. = 111 + _^1

2

( 48 · 20 ) Bor 48, = 111,  = P = 20 16 +^16 +^16

S.A. = 591 Simplify.

The surface area of the pyramid is 591 square meters.

a. Find the surface area of a square pyramid that has a slant height

of 8 centimeters and a base length of 5 centimeters.

GIFT BOXES Rachel is making gift boxes in the shape of square

pyramids for party favors. They have a slant height of 3 inches

and base edges 2.5 inches long. How many square inches of card

stock are used to make one gift box?

S.A. = B + _^1

2

P Surface area of a pyramid

S.A. = 6.25 + _^1

2

( 10 · 3 ) P = 4(2.5) or 10,  = 3, B = 2.5^2 or 6.25

S.A. = 21.25 Simplify.

So, 21.25 square inches of card stock are used to make one gift box.

b. PERFUME Amado purchased a bottle of perfume that is in the

shape of a square pyramid. The slant height of the bottle is

4.5 inches and the base is 2 inches. Find the surface area.

Perimeter of a Square

P = 4 s

Real-World Link

Half of the paper

America consumes is

used to wrap and

decorate consumer

products.

RR

Lesson 2E Surface Area 595

592_599_C10_L2_895130.indd 595 1/4/10 2:56 PM