Glencoe Math: Course 2, Volume 2
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Glencoe Math: Course 2, Volume 2 View details
5. Volume of Pyramids
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Exercise 3 Page 657

Use the formula for the volume of a pyramid.

42 cubic feet

Practice makes perfect

We want to find the volume of the following pyramid.

We can calculate the volume of a pyramid using the following formula. V=1/3Bh Here, B is the area of the base, and h is the height. The base of our pyramid is a right triangle with legs measuring 7 feet and 6 feet. Since the legs are perpendicular to each other, every leg is also the height falling onto the other leg. Therefore, the area B of a right triangle is half the product of the legs. Let's find this area!
B = 1/2( 7)( 6)
B = 1/2(42)
B = 42/2
B = 21
The base's area B is 21 square feet. The height h is 6 feet. Let's substitute these values into the formula and calculate V.
V=1/3Bh
V=1/3( 21)( 6)
â–Ľ
Simplify right-hand side
V=1/3(126)
V=126/3
V=42
The volume of the pyramid is 42 cubic feet.