1. S URFACE A REAS OF S PHERES

3. Surface Area of a Sphere Find the surface area of the sphere. Round to the nearest tenth. S=4  r 2 Surface area of a sphere =4  (4.5) 2 Replace r with 4.5. ≈254.5Simplify. Answer:254.5 in 2

4. A.462.7 in 2 B.473.1 in 2 C.482.6 in 2 D.490.9 in 2 Find the surface area of the sphere. Round to the nearest tenth.

5. Use Great Circles to Find Surface Area A. Find the surface area of the hemisphere. Find half the area of a sphere with the radius of 3.7 millimeters. Then add the area of the great circle.

6. Use Great Circles to Find Surface Area Surface area of a hemisphere Answer: about 129.0 mm 2 Replace r with 3.7. Use a calculator. ≈ 129.0

7. Use Great Circles to Find Surface Area B. Find the surface area of a sphere if the circumference of the great circle is 10  feet. First, find the radius. The circumference of a great circle is 2  r. So, 2  r = 10  or r = 5.

8. Use Great Circles to Find Surface Area Answer: about 314.2 ft 2 S=4  r 2 Surface area of a sphere =4  (5) 2 Replace r with 5. ≈314.2Use a calculator.

9. Use Great Circles to Find Surface Area C. Find the surface area of a sphere if the area of the great circle is approximately 220 square meters. First, find the radius. The area of a great circle is  r 2. So,  r 2 = 220 or r ≈ 8.4.

10. Use Great Circles to Find Surface Area Answer: about 886.7 m 2 S=4  r 2 Surface area of a sphere ≈4  (8.4) 2 Replace r with 5. ≈886.7Use a calculator.

11. A.110.8 m 2 B.166.3 m 2 C.169.5 m 2 D.172.8 m 2 A. Find the surface area of the hemisphere.

12. A.100.5 ft 2 B.201.1 ft 2 C.402.2 ft 2 D.804.3 ft 2 B. Find the surface area of a sphere if the circumference of the great circle is 8  feet.

13. A.320 ft 2 B.440 ft 2 C.640 ft 2 D.720 ft 2 C. Find the surface area of the sphere if the area of the great circle is approximately 160 square meters.