McGraw Hill Integrated II, 2012
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McGraw Hill Integrated II, 2012 View details
2. Surface Areas of Prisms and Cylinders
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Exercise 6 Page 817

Use the formula for the surface area of a cylinder.

Lateral Area: 1409.9 cm^2
Surface Area: 2063.6 cm^2

Practice makes perfect

We are asked to find the lateral area and surface area of the given cylinder.

We will do these things one at a time.

Lateral Area

Let's recall the formula for the lateral area L of a right cylinder. L=2π rh Here, r is the radius of the base, and h is the height of the cylinder. Let's start by finding the radius of the base. In the diagram, we see that the base is a circle with diameter equal to 20.4cm. Its radius is exactly the half of the length of the diameter. r = 20.4/2 ⇒ r = 10.2 We also see in the diagram that the height of the solid is 22cm. With this information, we can find the lateral area of the prism.
L=2 π r h
L=2 π ( 10.2)( 22)
L=448.8 π
L=1409.946783...
L≈ 1409.9
The lateral area of the cylinder is 1409.9cm^2.

Surface Area

Let's recall the formula for the surface area of a cylinder. S=L+2π r^2 In this formula, r is the radius of the base and L is the lateral area of the cylinder. Substituting r with 10.2 and L with 1409.9 into the formula, we can find the value of S. Let's do it!
S=L+2π r^2
S=1409.9+2π( 10.2)^2
Evaluate right-hand side
S=1409.9+2π(104.04)
S=1409.9+208.08π
S = 1409.9 + 653.702599 ...
S≈ 1409.9 + 653.7
S≈ 2063.6
The surface area of the cylinder is about 2063.6 cm^2.