Glencoe Math: Course 3, Volume 2
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Glencoe Math: Course 3, Volume 2 View details
5. Surface Area of Cones
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Exercise 5 Page 635

279.5 cm^2

Practice makes perfect

The given solid is a cone.

To calculate the surface area of a cone, we can use the known formula where r is the radius of the base and l is the slant height of the cone. S=Ï€ rl+Ï€ r^2 Looking at the diagram, we know that the radius of the cone's base is 5.95 centimeters and that the the slant height of the cone equals 9 centimeters. By substituting r with 5.95 and l with 9 into the formula, we can calculate S.

S=Ï€ rl+Ï€ r^2
S=Ï€( 5.95)( 9)+Ï€( 5.95)^2
â–¼
Evaluate right-hand side
S=Ï€(5.95)( 9)+Ï€(35.4025)
S=53.55Ï€+35.4025Ï€
S=88.9525Ï€
S=279.452520...
S≈ 279.5

The surface area of the cone is approximately 279.5 square centimeters.