Circumference
Area of a Circle
Diameter and Radius
Grab Bag
100
Compute the circumference of a circle with a radius length of 12 inches.
C=2(pi)r
The circumference is approximately 75.36 inches.
100
Compute the area of a circle with a radius length of 6.5 centimeters.
A=pi*r^2
The area is approximately 132.67 square centimeters.
100
The diameter of a circle is 1225 inches. Find the length of its radius.
r=d/2
612.5 inches
100
Identify a radius of the circle.
GA, GB, GC, GD, GE or GF
200
C=pi*d
The circumference is approximately 37.68 cm
200
The diameter of a circle is 8 centimeters. What is the area?
First
First r=d/2
Then A=pi*r^2
r = 50.24 inches
200
Compute the diameter of a circle with a circumference of 34 feet.
d=C/pi
The diameter is approximately 10.83 feet.
200
Find the rea of the shaded region. Round your answer to the nearest hundredth.
(hint add up the areas of the circles and then subtract from the area of the square)
Area of shaded region = 38.88 square centimeters.
300
The circumference of a circle is 188 meters. What is the approximate radius of the circle? Round to the nearest hundredth.
C/(2*pi)=r
r ≈ 29.94 inches
300
The radius is 8 cm
300
Compute the radius of a circle with a circumference of 255 inches.
r=C/(2*pi)
r ≈ 40.61 inches
300
The circumference of a circle is 56.52 centimeters. Calculate the radius of the circle. Round to the nearest hundredth.
The radius is approximately 8.96 cm.
400
C=pi*d
The circumference is approximatrely 31.4 inches
400
A circular silver tray has a diameter of 24 centimeters. What is the area of the top surface of the tray?
First r=d/2
Then A=pi*r^2
≈ 452.16 square centimeters
400
The circumference of a circle is 47.73 millimeters. Calculate the diameter of the circle.
d=C/pi
15.2 millimeters
400
You collect coins. One of your favorite coins is a silver-colored coin showing a man’s portrait. The radius of the coin is 12 millimeters. What is the diameter of the coin? What is the circumference of the coin? What is the area of the coin?
Diameter = 24 millimeters
Circumference = 75.36 millimeters
Area = 452.16 square millimeters
500
Keiko wants to put a ribbon border along the edge of her round tablecloth. If the diameter of the tablecloth is 42 inches, how many inches of ribbon will Keiko need to buy?
C=pi*d
Keiko will need to buy 132 inches of ribbon.
500
Mekhi wants to cover the top of a circular pond to keep leaves out of the pond. If the diameter of the pond is 12 feet, what is the area of the top of the cover (the portion of the cover that covers the surface of the pond)?
First r=d/2
Then A=pi*r^2
The area of the top of the cover will be approximately 113.04 square feet.
500
Washington High School is building a new running track. The track is constructed from a rectangle and two semicircles. The inside of the track will be all grass. Determine the area of grass needed to fill in the track. Round to the nearest whole number
Area of the square is s^2
Area of the circle is pi*r^2
≈ 14,792 square feet
500
You buy a new wheel for your bicycle. The diameter of the bicycle wheel is 22 inches. What is the radius of the bicycle wheel? What is the circumference of the bicycle wheel? What is the area of the bicycle wheel?
Radius = 11 inches
Circumference = 69.08 inches
Area = 379.94 square inches