FiveMinute Check over Lesson 11 3 Main Idea

Five-Minute Check (over Lesson 11– 3) Main Idea and Vocabulary Key Concept: Area of a Circle Example 1: Find the Area of a Circle Example 2: Real-World Example 3: Test Example

• Find the areas of circles. • Sector: a region of the circle bounded by 2 radii.

Find the Area of a Circle Find the area of the circle shown here. A = πr 2 Area of a circle A = π ● 42 Replace r with 4. π × 4 x 2 ENTER 50. 26548246 Answer: about 50. 3 cm 2

Find the area of the circle shown here. A. approximately 32. 97 ft 2 B. approximately 65. 9 ft 2 C. approximately 121. 3 ft 2 D. approximately 346. 4 ft 2 1. 2. 3. 4. A B C D

KOI Find the area of the koi pond shown. The diameter of the koi pond is 3. 6 m. Therefore, the radius is 1. 8 m. A = πr 2 Area of a circle A = π(1. 8)2 Replace r with 1. 8. A ≈ 10. 2 Multiply. Answer: about 10. 2 m 2

COINS Find the area of a nickel whose diameter is 2. 1 centimeters. A. approximately 2. 5 cm 2 B. approximately 3. 3 cm 2 C. approximately 3. 5 cm 2 D. approximately 4. 5 cm 2 1. 2. 3. 4. A B C D

Mr. Mc. Gowan made an apple pie with a diameter of 10 inches. He cut the pie into 6 equal slices. Find the approximate area of each slice. A 3 in 2 B 13 in 2 C 16 in 2 D 52 in 2 Read the Item You can use the diameter to find the total area of the pie and then divide that result by 6 to find the area of each slice. Solve the Item Find the area of the whole pie.

A = πr 2 Area of a circle A = π(5)2 Replace r with 5. A ≈ 78 Multiply. Find the area of one slice: 78 ÷ 6 = 13 Answer: B

MERRY-GO-ROUND The floor of a merry-go-round at the amusement park has a diameter of 40 feet. The floor is divided evenly into eight sections, each having a different color. Find the approximate area of each section of the floor. A. 157 ft 2 B. 225 ft 2 C. 264 ft 2 D. 312 ft 2 1. 2. 3. 4. A B C D

End of the Lesson

Five-Minute Check (over Lesson 11– 3) Image Bank Math Tools Area of Trapezoids Drawing 3 -D Figures Area of Polygons

(over Lesson 11 -3) Find the circumference of the circle. Use 3. 14 for . Round to the nearest tenth if necessary. radius = 5 ft diameter = 11. 2 in. Find the diameter of the circle. Use 3. 14 for . Round to the nearest tenth if necessary. C = 30 ft, diameter = ___ ft C = 96 cm, diameter = ___ cm 1. 2. 3. 4. A coffee can has a circumference of 216 mm. Which equation could be used to find the diameter of the can in inches? A B C D

(over Lesson 11 -3) Find the circumference of the circle. Use 3. 14 for . Round to the nearest tenth if necessary. radius = 5 ft A. 15. 7 ft B. 31. 4 ft C. 78. 5 ft D. 3. 14 ft 1. 2. 3. 4. A B C D

(over Lesson 11 -3) Find the circumference of the circle. Use 3. 14 for . Round to the nearest tenth if necessary. diameter = 11. 2 in. A. 35. 2 in. B. 17. 6 in. C. 70. 3 in. D. 7. 0 in. 1. 2. 3. 4. A B C D

(over Lesson 11 -3) Find the diameter of the circle. Use 3. 14 for . Round to the nearest tenth if necessary. C = 30 ft, diameter = ___ ft A. 9. 5 B. 19. 1 C. 9. 6 D. 4. 8 1. 2. 3. 4. A B C D

(over Lesson 11 -3) Find the diameter of the circle. Use 3. 14 for . Round to the nearest tenth if necessary. C = 96 cm, diameter = ___ cm A. 24 B. 15. 3 C. 3. 0 D. 30. 6 1. 2. 3. 4. A B C D

(over Lesson 11 -3) A coffee can has a circumference of 216 mm. Which equation could be used to find the diameter of the can in inches? A. 216 = d B. C = × 108 C. 108 = × d D. C = × 14. 7 1. 2. 3. 4. A B C D