1. Geometry Today: Class Announcements 12.5 Homework Questions/Check 12.6 Notes / Break / Finish 12.6 Notes Begin Homework

2. Chapter 12 Formulas F + V = E + 2 Surface Area Prism S = 2B + Ph Cylinder S = 2B + Ch Pyramid S = B + ½P l Cone S = B + ½C l Sphere S = ? Volume Prism V = Bh Cylinder V = Bh Pyramid V = 1/3 Bh Cone V = 1/3 Bh Sphere V = ?

3. 12.6 Area and Volume of Spheres Objectives: Find the surface area of a sphere Find the volume of a sphere Use spheres in real life Vocabulary: center, radius, diameter and chord of sphere, great circle, hemisphere

4. Surface Area – number of square tiles to cover the surface of a solid Volume – number of cubic units in the interior of a solid Spheres

5. radius Anatomy of Spheres center diameter great circle hemisphere

6. 12.11 Surface Area of a Sphere The surface area S of a sphere with radius r is S = 4  r 2. 64  cm 2  201.06 cm 2 Find the surface area of the sphere if r = 4 cm. r Include units!

7. Find the surface area of a sphere with radius of 2”. 16  in 2  50.27 in 2 2” If you double the radius, will the surface area double? 64  in 2  201 in 2 No, it quadrupled (2 2 )

8. A leather ball has a radius of 5 inches. Estimate the amount of leather used to cover the ball? Use mental math to determine your answer. 314 in 2

9. Find the surface area of a globe with a diameter of 20 inches. 400  in 2  1256.64 in 2

10. The circumference of a great circle of a sphere is 15.5  meters. What is the surface area of the sphere? 240.25  m 2  755 m 2

11. The great circle formed by the equator of Mars has a circumference of about 13,300 miles. Estimate the surface area of Mars.  56,300,000 miles 2

12. Break Time Use this time to relax, stretch out, talk to a neighbor, or try to find the hidden tiger…

13. 12.12 Volume of a Sphere The volume V of a sphere with radius r is V =  r 3. 36  cm 3  113.10 cm 3 Find the volume of the sphere if r = 3 cm. r If you double the radius, will the volume double? 288  cm 3  904.78 cm 3 No, it octupled (2 3 )

14. The great circle formed by the equator of Mars has a circumference of about 13,300 miles. Estimate the volume of Mars.  39,729,000,000 miles 3

15. What is the radius to the nearest hundredth of a sphere molded from the cylinder of modeling clay shown?  3.63 cm 2 cm 16 cm

16. You melt a 4 inch diameter sphere of wax and pour it into a cylindrical 2 inch diameter candle mold. How tall can you make the candle?  10.67 in

17. Assignment:  12.6 pgs. 762-764 #10-18, 20-24, 27, 29  Chapter 12 Test on Thursday, May 24 th !  Final exam on Friday, June 1 st ! 12.6 Area and Volume of Spheres