Circles,Circles,Circles!

Vocabulary

100

Name the collection of points equidistant from a point called the center

Circle

200

Name the line segment that cuts a circle in half

Diameter

300

What do you call half of the diameter?

radius

400

The outside measurement of a circle (Hint: similar to perimeter)

Circumference

500

The part of a circle described by a central angle

Arc

Circumference

100

What is the circumference of a circle if:

the diameter = 14 yds?

43.96 yd

200

What is the circumference of a circle if:

the diameter = 18 yds?

56.52 yds

300

What is the circumference of a circle if:

the diameter = 16.8 yds? (round to nearest tenth)

52.8 yds

400

What is the circumference of a circle if:

the diameter = 14.8 yds? (round to nearest tenth)

46.5 yds

500

What is the circumference of a circle if:

the diameter = 11.8 yds? (round to nearest tenth)

37.1 yds

Arc Length

100

What is the length of an arc with a central angle of 90 degrees in a circle with circumference 4pi?

pi

200

What is the length of an arc with a central angle of 60 degrees in a circle with diameter 6?

60/360 * 6pi = 1/6 * 6pi = pi

300

see google slide #1

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400

An arc with central angle 90 degrees has a length of 10 pi. What is the circumference of the circle?

10pi = 90/360 * C = 1/4 C

C = 40pi

500

An arc with central angle 120 degrees has a length of 12pi. What is the diameter of the circle?

36

Word Problems

100

Trevor needs a new bicycle tire. His tire has a circumference of about 112 inches. What is the diameter of his tire? (round to the nearest tenth place)

35.7 in

200

Gene’s frying pan is 14.5 inches in diameter. What is the circumference of his frying pan? (round to the nearest tenth place)

45.5 in

300

Brad uses 31.4 meters of plastic edging to create the border of a circular flower garden in his yard.  How far is it from the center of the garden to the edge?

5 m

400

Macy measures a truck’s tire mark for one complete revolution as 120.48 inches long. What is the diameter of the tire? (round to the nearest tenth place)

38.4 in

500

The circular fountain in front of the courthouse has a radius of 9.4 feet. What is the circumference of the fountain? Round to the nearest tenth.

59 ft

Arc Area and Angles

100

A sector with a radius of 10cm and has a angle measure of 35⁰

30.54 

200

A circle with a diameter of 20cm and a sector with an angle of 45^o. What is the area of this sector?

39.26 or 12.5pi

300

See google slide #2

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400

See google slide #3

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500

See google slide #4

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