Page 58 - Math Course 3 (Book 2)

Geometric Surface Area: Spheres

Surface Area Standardized Test Example
Find the approximate surface area of a hemisphere Find the surface area of a ball with a circumfer-
with a radius of 6.4 inches ence of 18 inches to determine how much leather
is needed to make the ball.
A. 128.7 in²
B. 257.4 in² A. 51.6 in²
C. 386.0 in² B. 254.5 in²
D. 514.7 in² C. 412.5 in²
D. 103.1 in²

Answer Answer

Skill Practice!

In the figure, A is the center of the sphere, and plane T intersects the sphere in circle E. Round to the nearest
tenth if necessary.

1. If AE = 5 and DE = 12, find AD.

2. If AE = 7 and DE = 15, find AD.

3. If the radius of the sphere is 18 units and the radius of ⊙E is 17 units, find AE.

4. If the radius of the sphere is 10 units and the radius of ⊙E is 9 units, find AE.

5. If M is a point on ⊙E and AD = 23, find AM.

Find the surface area of each sphere or hemisphere. Round to the nearest tenth.

6. 7. a hemisphere with a radius of the great circle 8 yards

8. a hemisphere with a radius of the great circle 2.5 millimeters

9. a sphere with the area of a great circle 28.6 inches

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