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Glencoe Math: Course 3, Volume 2

GM

Glencoe Math: Course 3, Volume 2 View details

5. Surface Area of Cones

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Exercise 5 Page 635

Use the formula for the surface area of a cone.

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=π rl+π 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=π rl+π r^2

r= 5.95, l= 9

S=π( 5.95)( 9)+π( 5.95)^2

▼

Evaluate right-hand side

Calculate power

S=π(5.95)( 9)+π(35.4025)

Multiply

S=53.55π+35.4025π

Add terms

S=88.9525π

Use a calculator

S=279.452520...

Round to 1 decimal place(s)

S≈ 279.5

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

Subchapter links

Guided Practice p.634

Independent Practice p.635-636

H.O.T. Problems p.636

Extra Practice p.637

Standardized Test Practice p.638

Common Core Review p.638