Radius & Diameter
Circumference and Area
Circles in the real world
Circle Challenge
Random Trivia
100
The diameter is 10 inches. Find the radius.
5 inches
100
A circle has a diameter of 12 inches. What is the circumference in terms of pi?
12pi
100
A bicycle wheel has a radius of 1 foot. If the bicycle wheel rotates one time, what distance is traveled? (use 3.14 for pi)
6.28 feet
100
A circle has an area of 12 ft squared. It is cut into 4 equal pieces. What is the area of each piece?
3 ft2
100
What is the capital of Rhode Island?
Providence
200
The radius is 25 feet. Find the diameter.
50 feet
200
A circle has a diameter of 25 inches. What is the circumference? (Use 3.14 for pi)
78.5 inches
200
A large Jeep has a tire with a radius of 18 inches. Find the circumference of the wheel. (use 3.14 for pi)
113.04 inches
200
A circle has a circumference of 37.68 feet. What is the area of half of the circle? (use 3.14 for pi)
56.52 ft squared
200
What is the most used spice in the world?
Black pepper
300
The circumference of the circle is 56.52 cm. Find the diameter.
18 inches
300
A circle has a radius of 50 miles. What is the area of the circle? (use 3.14 for pi)
7850 mi2
300
John owns a circular pool in his back yard. If he swims around the pool, he swims 30pi meters. What is the radius of this circle?
15 meters
300
A pizza is 16 inches long (the diameter). The pizza is cut into 8 pieces. What is the length of crust (circumference) on each piece?
What is 6.28 in?
300
What letter does not appear in the name of any of the 50 states?
Q
400
The circumference of a circle is
24pi
inches. Find the diameter.
12 inches
400
A circle has a diameter of 16. Find the area in terms of pi.
64pi
400
Olivia is making a pair of hoop earrings that measure 4 inches across. How much metal will she need to make both earrings?
25.12 inches
400
A pizza is 16 inches long (diameter). It is cut into 4 pieces. Jane eats 3 of the pieces. What is the area of pizza she is eating? (use 3.14 for pi)
150.72 in2
400
What is the largest organ of the human body?
Skin
500
A circle has a circumference of
25pi cm.
Find the radius.
12.5 centimeters
500
A circle has a circumference of 18.84 cm. What is the area? (use 3.14 for pi)
28.26 square cm
500
A pizza with a diameter of 22 inches cost $28. How much does one square inch of pizza cost?
About $0.07 per square inch.
500
What is the area of the shaded region? (use 3.14 for pi)
37.68 square units
500
If you had a room with ___ people in it, there is a 50% chance that two people will share a birthday.
23 people
(if you have 57 people, that probability shoots up to 99%!)