Parts of a Circle and Circumference

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Show your work for each problem.

1.
What is the relationship between diameter and radius?
1. a)
2. b)
3. c)
4. d)
2.
Which formula correctly calculates the circumference using the radius?
1. a)
2. b)
3. c)
4. d)
3.
A circle has a radius of cm. What is its diameter in cm?
4.
A circle has a diameter of cm. What is its radius in cm?
5.
Find the circumference of a circle with radius cm. Use .
6.
Find the circumference of a circle with diameter m. Use .
7.
A circular pond has a circumference of m. Using , what is its diameter?
1. a) m
2. b) m
3. c) m
4. d) m
8.
A wheel has a circumference of cm. What is its radius in cm? Use .
9.
A circular track has a circumference of m. Find its radius. Use and round to one decimal place.
10.
A pizza has a diameter of cm. How far does a pizza cutter travel if it goes around the entire edge? Use .
11.
If you double the radius of a circle, what happens to its circumference?
1. a)It stays the same
2. b)It doubles
3. c)It triples
4. d)It quadruples
12.
A bicycle wheel makes complete rotations to travel km. What is the diameter of the wheel in cm? Use and round to the nearest whole number.
13.
A circular fountain has a fence around it. The fence is meters from the edge of the fountain. If the fountain's diameter is m, how long is the fence? Use .
14.
Two circles have circumferences of cm and cm. What is the difference between their radii in cm? Use .
15.
A semicircle has a diameter of cm. What is the total perimeter (curved part + straight edge)? Use .
1. a) cm
2. b) cm
3. c) cm
4. d) cm