FiveMinute Check over Lesson 11 7 ThenNow New

Over Lesson 11– 7 Find the circumference of the circle to the nearest tenth.

Over Lesson 11– 7 The diameter of a circle is 5. 7 feet. Find

Over Lesson 11– 7 A. 9. 9 in. B. 10 in. C. 10. 1

Over Lesson 11– 7 What is the approximate circumference of a plate that has

You have already found the circumference of a circle. (Lesson 11– 7) • Find

Find Areas of Circles A. Find the area of the circle. Round to the

Find Areas of Circles B. Find the area of the circle. Round to the

A. Find the area of the circle. Round to the nearest tenth. A. 38.

B. Find the area of the circle. Round to the nearest tenth. A. 16.

Use Area of Circles to Solve Problems PICTURE FRAMES The rectangular matting for a

Use Area of Circles to Solve Problems Find the area of the rectangle minus

The rectangular matting for a picture frame has a circular cutout as shown in

Find the Area of a Sector Find the area of the shaded sector in

To the nearest tenth, what is the area of the shaded sector in the

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Five-Minute Check (over Lesson 11– 7) Then/Now New Vocabulary Key Concept: Area of a Circle Example 1: Find Areas of Circles Example 2: Real-World Example: Use Area of Circles to Solve Problems Key Concept: Area of a Sector Example 3: Find the Area of a Sector

Over Lesson 11– 7 Find the circumference of the circle to the nearest tenth. A. 50. 2 mm B. 50 mm C. 25. 1 mm D. 25 mm

Over Lesson 11– 7 Find the circumference of the circle to the nearest tenth. A. 37. 7 yd B. 34. 4 yd C. 18. 8 yd D. 18. 4 yd

Over Lesson 11– 7 The diameter of a circle is 5. 7 feet. Find the circumference of the circle. A. 17. 1 ft 2 B. 17. 9 ft C. 35. 8 ft 2 D. 35. 8 ft

Over Lesson 11– 7 A. 9. 9 in. B. 10 in. C. 10. 1 in. D. 10. 2 in.

Over Lesson 11– 7 What is the approximate circumference of a plate that has a radius of 5. 5 inches? A. 12. 7 in. B. 17. 2 in. C. 34. 6 in. D. 35. 4 in.

You have already found the circumference of a circle. (Lesson 11– 7) • Find areas of circles. • Find areas of sectors.

• sector • central angle

Find Areas of Circles A. Find the area of the circle. Round to the nearest tenth. Estimate A = r 2 A ≈ 3 ● 172 or 867 Area of a circle = ● 172 Replace r with 17. = ● 289 Evaluate 172. 907. 9 ft 2 Use a calculator. Answer: The area is about 907. 9 square feet. Check 907. 9 ≈ 867

Find Areas of Circles B. Find the area of the circle. Round to the nearest tenth. Estimate A = r 2 A ≈ 3 ● 42 or 48 Area of a circle = ● 4. 152 Replace r with 4. 15. = ● 17. 2225 Evaluate (4. 15)2. 54. 1 cm 2 Use a calculator. Answer: The area is about 54. 1 square centimeters. Check 54. 1 ≈ 48

A. Find the area of the circle. Round to the nearest tenth. A. 38. 5 m 2 B. 44. 0 m 2 C. 153. 9 m 2 D. 615. 8 m 2

B. Find the area of the circle. Round to the nearest tenth. A. 16. 3 in 2 B. 32. 7 in 2 C. 84. 9 in 2 D. 339. 8 in 2

Use Area of Circles to Solve Problems PICTURE FRAMES The rectangular matting for a picture frame has a circular cutout for the photograph, as shown in the figure. What is the area of the mat? Round to the nearest tenth.

Use Area of Circles to Solve Problems Find the area of the rectangle minus the area of the circle. Area of rectangle Area of circle A= ℓw – r 2 = 18 ● 12 – ● 42 Replace ℓ with 18, w with 12, and r with 4. = 216 – 16 Simplify. 165. 7 Use a calculator. Answer: The area is about 165. 7 sq. in.

The rectangular matting for a picture frame has a circular cutout as shown in the figure. What is the approximate area of the matting? A. 150. 6 in 2 B. 131. 7 in 2 C. 124. 6 in 2 D. 79 in 2

Find the Area of a Sector Find the area of the shaded sector in the circle. Round to the nearest tenth. Area of a sector Replace N with 120 and r with 6. Simplify. Use a calculator. Answer: The area is about 37. 7 m 2.

To the nearest tenth, what is the area of the shaded sector in the circle? A. 4. 2 in 2 B. 16. 8 in 2 C. 33. 5 in 2 D. 66. 0 in 2