1. Splash Screen

2. Lesson Menu Five-Minute Check (over Lesson 12–5) Then/Now Key Concept: Lateral and Surface Area of Cylinders Example 1: Surface Area of a Cylinder Example 2: Real-World Example: Compare Surface Areas of Cylinders

3. Over Lesson 12–5 A.A B.B C.C D.D 5-Minute Check 1 A.197.6 cm 2 B.204.7 cm 2 C.247.6 cm 2 D.274.4 cm 2 Find the lateral area of the figure.

4. Over Lesson 12–5 A.A B.B C.C D.D 5-Minute Check 2 A.96 in 2 B.98 in 2 C.106 in 2 D.108 in 2 Find the surface area of the figure.

5. Over Lesson 12–5 A.A B.B C.C D.D 5-Minute Check 3 A.2.4 m 2 B.2.6 m 2 C.3.6 m 2 D.3.8 m 2 Find the lateral area of a cube with a length of 0.8 meter.

6. Over Lesson 12–5 A.A B.B C.C D.D 5-Minute Check 4 A.512 in 2 B.520 in 2 C.570 in 2 D.594 in 2 Amy needs to wrap a box that is 18 inches long, 11 inches wide, and 3 inches high. What is the minimum amount of wrapping paper that she needs?

7. Over Lesson 12–5 A.A B.B C.C D.D 5-Minute Check 5 A.3,360 in 2 B.5,760 in 2 C.7,630 in 2 D.28,800 in 2 How much wood is needed to make a rectangular toy box that measures 40 inches long, 30 inches wide, and 24 inches high?

8. Then/Now You have already found the lateral areas and surface areas of prisms. (Lesson 12–5) Find lateral and surface areas of cylinders. Compare surface areas of cylinders.

9. Concept

10. Example 1 A Surface Area of a Cylinder A. Find the lateral area and surface area of the cylinder. Round to the nearest tenth. Lateral Area L =2πrh =2π(5)(8) =80πexact answer ≈251.3 in 2 approximate answer The lateral area is about 251.3 square inches.

11. Example 1 A Surface Area of a Cylinder Surface Area S =L + 2πr 2 =80π + 2π(5) 2 =130π exact answer ≈ 408.4 in 2 approximate answer The surface area is about 408.4 square inches. Answer: L ≈ 251.3 in 2, S ≈ 408.4 in 2

12. Example 1B Surface Area of a Cylinder The lateral area is about 537.2 square feet. Lateral Area L =2πrh =2 π 9 9.5 =171π =537.2 ft 2 B. Find the lateral area and surface area of the cylinder. diameter of 18 feet and height of 9.5 feet The diameter is 18 feet, so the radius is or 9 feet.

13. Surface Area S =L + 2πr 2 =171π + 2π(9) 2 =171π + 162π ≈ 1046.2 ft 2 Example 1B Surface Area of a Cylinder The surface area is about 1046.2 square feet. Answer: L ≈ 537.2 ft 2, S ≈ 1046.2 ft 2

14. A.A B.B C.C D.D Example 1A CYP A.lateral area, 1082.0 in 2 ; surface area, 1504.4 in 2 B.lateral area, 1082.0 in 2 ; surface area, 3852.9 in 2 C.lateral area, 2163.9 in 2 ; surface area, 2586.4 in 2 D.lateral area, 4436.1 in 2 ; surface area, 4858.6 in 2 A. Find the lateral area and the surface area of the cylinder. Round to the nearest tenth.

15. A.A B.B C.C D.D Example 1B CYP A.lateral area, 47.1ft 2 ; surface area, 56.5 ft 2 B.lateral area, 94.2 ft 2 ; surface area, 150.8 ft 2 C.lateral area, 141.4 ft 2 ; surface area, 197.9 ft 2 D.lateral area, 188.5 ft 2 ; surface area, 301.6 ft 2 B. Find the lateral area and the surface area of the cylinder. Round to the nearest tenth. diameter of 6 feet and height of 5 feet

16. Example 2 Compare Surface Areas of Cylinders MANUFACTURING A company manufactures dowel rods. Rod A has a diameter of 3 inches and a height of 12 inches. Rod B has a diameter of 1 inch and a height of 36 inches. Which rod has the larger surface area? The diameter of Rod A is 3 inches, so radius is 1.5 inches. Its height is 12 inches. The diameter of Rod B is 1 inch, so radius is 0.5 inch. Its height is 36 inches. Find the surface area of both rods.

17. Example 2 Compare Surface Areas of Cylinders Rod A S = L + 2πr 2 = 2πrh + 2πr 2 = 2π(1.5)(12) + π(1.5) 2 = 36π + 2.25π ≈ 120.2 in 2 Rod B S = L + 2πr 2 = 2πrh + 2πr 2 = 2π(0.5)(36) + π(0.5) 2 = 36π + 0.25π ≈ 113.9 in 2 Answer: Rod A has the larger surface area.

18. A.A B.B C.C D.D Example 2 A.Brand A’s container has the larger surface area. B.Brand B’s container has the larger surface area. C.The containers have the same surface area. D.It is not possible to determine the surface areas of the containers. A cylindrical Brand A oatmeal container has a radius of 5 inches and a height of 12 inches. Brand B uses a cylinder with a radius of 4 inches and a height of 14 inches. Which statement is true?

19. End of the Lesson