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Glencoe Math: Course 3, Volume 2 View details

5. Surface Area of Cones

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Exercise 22 Page 637

Use the formula for the surface area of a cone.

241.4 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 diameter of the cone's base is 7.8 centimeters. By dividing by 2, we get the radius of the base. r=7.8/2 ⇒ r = 3.9cm We are told that the slant height of the cone equals 15.8 centimeters. By substituting r with 3.9 and l with 15.8 into the formula, we can calculate S.

S=π rl+π r^2

SubstituteII

r= 3.9, l= 15.8

S=π( 3.9)( 15.8)+π( 3.9)^2

▼

Evaluate right-hand side

CalcPow

Calculate power

S=π(3.9)(15.8)+π(15.21)

Multiply

S=61.62π+15.21π

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