1. Warm Up Find each measurement. 1. the radius of circle M if the diameter is 25 cm 2. the circumference of circle X if the radius is 42.5 in. 3. the area of circle T if the diameter is 26 ft 4. the circumference of circle N if the area is 625 cm 2 12.5 cm 85 in. 169 ft 2 50 cm

2. Surface Areas and Volumes of Spheres Sections 12-7 and 13-3

3. Spheres A sphere is the locus of points in space that are a fixed distance from a given point called the center of a sphere. A radius of a sphere connects the center of the sphere to any point on the sphere. A hemisphere is half of a sphere. A great circle divides a sphere into two hemispheres

4. Surface Area of a Hemisphere? S = 3πr 2

5. Example: Find the surface area of the sphere. S = 2500 cm 2

6. Example: Finding Surface Area of Spheres Find the surface area of a sphere with diameter 76 cm. Give your answers in terms of . S = 4(38) 2 = 5776 cm 2

7. Example: Finding Surface Area of Spheres Find the surface area of a sphere with a great circle that has an area of 49 mi 2. 196 mi 2

8. Volume of a Hemisphere? V = 2/3πr 3

9. Example: Finding Volumes of Spheres Find the volume of the sphere. Give your answer in terms of . = 2304 in 3

10. Example: Finding Volumes of Spheres Find the volume of the hemisphere. = 2250 m 3

11. Lesson Quiz: Find each measurement. Give your answers in terms of . 1. the volume and surface area of the sphere 2. the volume and surface area of a sphere with great circle area 36 in 2 3. the volume and surface area of the hemisphere V = 36 cm 3 ; S = 36 cm 2 V = 288 in 3 ; S = 144 in 2 V = 23,958 ft 3 ; S = 3267 ft 2