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Vocab
Circumference
Area
Real-World Problems
Other
100

Define radius.

The distance from the center point of the circle to its circumference.

100
What is the formula for the circumference of a circle?
c=πd or c=π2r
100
What is the formula for area of a circle?
a=πr²
100
Anna is planting a circular garden. If the diameter of the garden is 21 meters, what is the circumference? Use 3.14 for π.
65.94 m
100
It takes two ________ to make a ________.
radii, diameter
200

Define diameter.

The distance across a circle (straight line)

200
Find the circumference of a circle with a diameter of 16 in using 3.14 for π. Round to the nearest hundredth if necessary.
50.24in
200

Find the area of a circle with a radius of 31.5 cm. Use 22/7 for π.

3118.5 cm²

200
The face of a circular sundial has a diameter of 18 inches. Find the area of the brass needed to cover one side of the sundial. Use 3.14 for π.
254.34 in²
200
The circumference measures the _________ of the circle.
Edge/Outside
300

Define area.

The entire space inside of a circle

300
Find the circumference of a circle with a radius of 17 in using 3.14 for π. Round to the nearest tenth.
106.8 in
300

Find the area of a circle with a radius of 3.4 m. Use 3.14 for π. Round to the nearest tenth.

36.3 m²

300

A store sells a circular rug that has a diameter of 8 ft. Find the amount of material needed to make this rug. Use 3.14 for π and round to the nearest tenth.

50.2 ft ²

300
The area measure the __________ of the circle.
inside
400

Define circumference.

The distance around a circle

400
Find the length of the arc of a semicircle that has a diameter of 5 in. Use 3.14 for π.
7.85 in
400
Find the area of a circle with a diameter of 11.6 m. Use 3.14 for π. Round to the nearest tenth.
105.6m².
400
Teresa is making a card for her mom. The card is in the shape of a circle and has a diameter of 7 in. She wants to put ribbon around the edge of her card. How much ribbon will she need?
21.98 in
400
What are the two most commonly used estimates for π?
3.14 and 22/7
500

Define π (Pi)

•The ratio of circumference to the diameter in ANY circle

π = Circumference/Diameter

500
Find the distance around a semicircle that has a radius of 11 in. Use 3.14 for π.
56.54 in
500
Find the area of a semicircle with a diameter of 14 in. Use 22/7 for π.
77in².
500
Riggoletto's Portraits specializes in making circular portraits of people. A large portrait is 30 inches in diameter. A medium portrait is 10 inches in diameter. Estimate the difference between the areas of the two sizes of portraits. Use 3.14 for π. Round your answer to the nearest whole number.
About 628 in²
500

What is the area of a half circle with a diameter of 15 meters? Use 3.14 for π.

88.3125 m2