1 / 9

EXAMPLE 1

a . . C = 2 πr. = 2 π 9. 56.55. ANSWER. The circumference is about 56.55 centimeters . EXAMPLE 1. Use the formula for circumference. Find the indicated measures. a. Circumference of a circle with radius 9 centimeters. SOLUTION. Write circumference formula.

fadey
Download Presentation

EXAMPLE 1

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. a. C=2 πr =2 π9 56.55 ANSWER The circumference is about 56.55centimeters. EXAMPLE 1 Use the formula for circumference Find the indicated measures. a. Circumference of a circle with radius 9 centimeters SOLUTION Write circumference formula. Substitute 9 forr. =18 Simplify. Use a calculator.

  2. 26 2 πr = 26 r = 2π 4.14 r ANSWER The radius is about 4.14meters. EXAMPLE 1 Use the formula for circumference Find the indicated measures. b. Radius of a circle with circumference 26 meters C =2 πr Write circumference formula. Substitute 26 for c. Divide each side by 2π. Use a calculator.

  3. The dimensions of a car tire are shown at the right. To the nearest foot, how far does the tire travel when it makes15revolutions? = 15 + 2 (5.5) d C = πd EXAMPLE 2 Use circumference to find distance traveled Tire Revolutions SOLUTION Find the diameter of the tire STEP 1 = 26 in. Find the circumference of the tire STEP 2 =π(26) ≈81.68in.

  4. 15 81.68 in EXAMPLE 2 Use circumference to find distance traveled STEP 3 Find the distance the tire travels in 15 revolutions. In one revolution, the tire travels a distance equal to its circumference. In 15 revolutions, the tire travels a distance equal to 15 times its circumference. = 1225.2 in

  5. 1 ft 1225.2 in. = 102.1 ft 12 in. ANSWER The tire travels approximately 102 feet. EXAMPLE 2 Use circumference to find distance traveled STEP 4 Use unit analysis. Change 1225.2 inches tofeet.

  6. C=d =5 15.71 for Examples 1 and 2 GUIDED PRACTICE 1. Find the circumference of a circle with diameter 5 inches. Find the diameter of a circle with circumference 17 feet. SOLUTION Write circumference formula. Substitute 5 for d. Use a calculator. The circumference is about 15.71in.

  7. C=d = d 17 17 d = 5.41 r for Examples 1 and 2 GUIDED PRACTICE circumference = 17 feet Write circumference formula. Substitute 17 for c. Divide each side by π. Use a calculator. The Diameter is about 5.41feet.

  8. C = πd 12 in. 500 ft. = 6000 in. 1 ft for Examples 1 and 2 GUIDED PRACTICE 2. A car tire has a diameter of 28 inches. How many revolutions does the tire make while traveling 500 feet? SOLUTION Find the circumference of the tire STEP 1 =π(28) ≈87.92in. STEP 2 Use unit analysis. Change 500 feet to inches.

  9. ANSWER The tire makes 68.2 revolutions. N 87.92 6000 N = 68.24 for Examples 1 and 2 GUIDED PRACTICE Find the number of revolutions STEP 3

More Related