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McGraw Hill Integrated II, 2012 View details

6. Surface Areas and Volumes of Spheres

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Exercise 4 Page 852

To find the area of a hemisphere calculate the area of half of a sphere with the same radius and add the area of the great circle.

161.4cm^2

Practice makes perfect

A hemisphere is half of a sphere.

To find the area of a hemisphere we need to calculate the area of half of a sphere with the same radius and add the area of the great circle. Surface Area of a Hemisphere [0.8em] A=1/2(4π r^2)+π r^2 We first need to calculate the radius. To do so we will consider the given fact that the circumference C of the great circle is approximately 26 cm. Let's recall the formula for circumference. C=2π r We can substitute 26 for C in this formula and solve for the radius r.

C=2π r

Substitute

C= 26

26=2π r

▼

Solve for r

DivEqn

.LHS /2π.=.RHS /2π.

26/2π=r

CancelCommonFac

Cancel out common factors

13/π=r