Define diameter and describe a way to find the diameter of a circle.
The distance across a circle; divide circumference by Pi, multiply radius x 2, measure with a ruler, etc.
100
The radius of the bike tire is 7 inches. What is the circumference of the bike tire?
42 inches or 3 feet 6 inches.
100
What is the radius of a circle if the diameter is 7 cm?
3.5 cm
100
What is the diameter of a circle if the circumference is 27 inches?
9 inches
100
A nickel has a diameter of 21 mm. What is the circumference of the nickel in centimeters?
6.3 cm
200
Define radius and describe a way to find the radius of a circle.
Distance from center of circle to any point on circle; divide diameter by 2. Divide circumference by pi, then by 2. Divide circumference by 6, measure with a ruler, etc.
200
The diameter of a circular wheel is approximately 28 inches. What is the circumference of the wheel?
84 inches or 7 feet.
200
What is the radius of a circle if the circumference is 18 inches?
3 inches
200
The circumference of the Earth is 24,901 miles. What method could be used to find the diameter of the Earth?
Divide 24,901 miles by pi
200
The circumference of an unbaked cookie is 3 inches. The diameter expands in the oven by one inch. What is the circumference of the cookie after it is baked?
6 inches
300
Define circumference and describe a way to find the circumference of a circle.
Distance around a circle; multiply Pi x diameter. Multiply 2 x Pi x radius.
300
How does the measure of circumference compare to the measure of the diameter and radius of a circle?
The circumference is approximately 3x the diameter and approximately 6x the radius.
300
A swimming pool has a circumference of 75 feet. What is the radius of the pool?
12.5 feet
300
The radius of a pizza is 6 inches. How many feet is the diameter of the pizza?
1 foot
300
Mr. Pursifull has a golf ball with a radius of 0.75 inches. The ball is 3 feet away from the hole. How many rotations does it need to travel to get there?
8 rotations
400
What is Pi?
Approx. 3, ratio of circumference to diameter, Greek symbol
400
Nick and Eliberto brought pies to class. Nick’s pie had a circumference of 27 inches. Eliberto’s pie had a radius of 4 inches. Who brought the pie with the larger circumference?
Nick brought the larger pie because the circumference of Eliberto’s pie is 24 inches.
400
A circular pizza has a circumference of about 24 inches. Write an equation that could be used to find the radius of the pizza.
r = 24/(2xpi)
400
Ms. Nelson plays softball every summer and uses a ball with a 12 inch circumference. What is the diameter of the softball?
4 inches
400
A Texas Star Ferris wheel at Fair Park has a diameter of 212 feet. Approximately how far will the Ferris wheel travel 5 rotations?
3,180 feet
500
What are the two formulas for calculating the circumference of a circle?
C=(pi)d C=2(pi)r
500
A spinning top has a diameter of 3 inches. It spins around for a total of 6 feet before it drops. How many times did it go around?
It goes around 8 times.
500
Mr. Hosey ran around a circular track 20 times for a total of 7,200 meters. What is the approximate radius of the track in meters?
60 meters
500
The standard NBA basketball has an approximate circumference of 30 inches. What would the diameter of the basketball hoop need to be for it to fall through the net?
A little more than 10 inches
500
A pitcher’s mound has a radius of 9 feet. Yu Darvish has a routine of walking halfway around the mound before beginning his warm up. How far does he walk?