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 2 Page 634

The lateral area of a right cone is half the product of the circumference of the base and the slant height.

282.7m^2

Practice makes perfect

We want to find the lateral area of the given cone.

To do so, we must know that the lateral area of a right cone is half the product of the circumference of the base and the slant height. L.A.=1/2* 2π r* l ⇔ L.A.=π rl In this formula, r is the radius and l is the slant height of the cone. Since we know that the diameter d is equal to 30, we can divide it by 2 and get the radius of the base. r=30/2 ⇒ r= 15 With this information we are able to calculate the lateral area of the cone. To do so, we will substitute r= 15 and l= 6 into the formula for the lateral area. Let's do it!
L.A.=π rl
L.A.=π ( 15)( 6)
L.A.=π (90)
L.A.=90π
L.A.=282.743338...
L.A.≈ 282.7
The lateral area of the given cone, rounded to the nearest tenth, is 282.7 square meters.