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McGraw Hill Integrated II, 2012

MH

McGraw Hill Integrated II, 2012 View details

2. Surface Areas of Prisms and Cylinders

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Exercise 7 Page 817

Use the formula for the surface area of a cylinder.

About 10.0 centimeters

Practice makes perfect

The can of soup, which has a surface area of S= 286.3 square centimeters, can be modeled by the following cylinder.

The radius of the base is r= 3.4 centimeters. We are asked to find the height of the can h and round the answer to the nearest tenth. Let's use the formula for the surface area of a cylinder and substitute the known values.

S=2π r h+2π r^2

S= 286.3, r= 3.4

286.3=2π ( 3.4) h+2π ( 3.4)^2

▼

Solve for h

Use a calculator

286.3= (21.362830...) h+72.633622...

Round to 1 decimal place(s)

286.3≈ 21.4 h+72.6

LHS-72.6=RHS-72.6

213.7≈ 21.4 h

.LHS /21.4.=.RHS /21.4.

9.985981... ≈ h

Rearrange equation

h≈ 9.985981...

Round to 1 decimal place(s)

h≈ 10.0

This tells us that the height of the can is about 10.0 centimeters.

Subchapter links

Exercises p.817-821