1. Lesson 1 MI/Vocab circle center radius diameter circumference pi Find the circumference and area of circles.

2. Lesson 1 Key Concept 1

3. Lesson 1 Ex1 Find the Circumferences of Circles Find the circumference of the circle. Round to the nearest tenth. Answer:The circumference is about 15.7 feet. C =  dCircumference of a circle C =   5 Replace d with 5. C = 5  This is the exact circumference. Use a calculator to find 5 . 5 15.70796327  × ENTER =

4. A.A B.B C.C D.D Lesson 1 CYP1 A.38.5 in. B.31.4 in. C.22.0 in. D.19.7 in. Find the circumference of the circle. Round to the nearest tenth.

5. Lesson 1 Ex2 Find the Circumferences of Circles Find the circumference of the circle. Round to the nearest tenth. Answer: The circumference is about 23.9 meters. C = 2  r Circumference of a circle C = 2    3.8Replace r with 3.8. C ≈ 23.9Use a calculator.

6. Lesson 1 CYP2 1.A 2.B 3.C 4.D A.9.4 m B.11.3 m C.18.5 m D.22.6 m Find the circumference of the circle. Round to the nearest tenth.

7. Lesson 1 Key Concept 2

8. Lesson 1 Ex3 Find the Areas of Circles Find the area of the circle. Round to the nearest tenth. Answer: The area is about 28.3 square yards. A =  r 2 Area of a circle A =   3 2 Replace r with 3. A =   9 Evaluate 3 2. A ≈ 28.3Use a calculator.

9. 1.A 2.B 3.C 4.D Lesson 1 CYP3 A.12.6 ft 2 B.14.1 ft 2 C.15.3 ft 2 D.17.4 ft 2 Find the area of the circle. Round to the nearest tenth.

10. Lesson 1 Ex4 Find the area of the circle. Round to the nearest tenth. Answer: The area is about 78.5 square inches. Find the Areas of Circles A =  r 2 Area of a circle A =   5 2 Replace r with half of 10 or 5. A =   25 Evaluate 5 2. A ≈ 78.5Use a calculator.

11. A.A B.B C.C D.D Lesson 1 CYP4 A.42.7 cm 2 B.50.3 cm 2 C.52.1 cm 2 D.54.6 cm 2 Find the area of the circle. Round to the nearest tenth.

12. Lesson 1 Ex5 POOLS The Patels have a circular pool with a radius of 12 feet. They plan on installing a 4-foot-wide walkway around the pool. What will be the area of the walkway? To determine the area of the walkway, you must subtract the area of the pool from the area of the outer circle that includes the pool and the walkway.

13. Lesson 1 Ex5 Area of Outer Circle A =  r 2 Area of a circle A =  (16) 2 Replace r with 12 + 4 or 16. A =   256 Evaluate 16 2.

14. Lesson 1 Ex5 Area of Pool A =  r 2 Area of a circle A =   12 2 Replace r with 12. A =   144 Evaluate 12 2.

15. Lesson 1 Ex5 Area of Walkway = Area of Outer Circle – Area of Pool Answer:The area of the walkway is about 351.9 square feet. ≈ 256  – 144  ≈ 351.9

16. A.A B.B C.C D.D Lesson 1 CYP5 A.62.8 ft 2 B.84.3 ft 2 C.99.2 ft 2 D.113.1 ft 2 POOLS The Shoemakers have a circular pond with a radius of 4 feet. They plan on installing a 2- foot-wide walkway around the pond. What will be the area of the walkway?