The distance from the center of a circle to the outside, also half of the diameter.
Radius
The Diameter of this circle is 25cm, what is the radius?

12.5cm
The radius of this circle is given, what is the diameter?

10cm
The diameter of the circle is 19cm, calculate the circumference.

59.69 cm
Calculate the area

78.5 in2
The longest part in a circle. From one edge to the other through the center.
Diameter
The diameter of the circle is 420km, what is the radius?

210km
The radius of the circle is given, what is the diameter?

42cm
Calculate the circumference. (units = feet)

81.68 ft
The radius of the eye is 4mm, what is the area?

50.24mm2
The distance around the circle.

Circumference
What is the radius of the ferris wheel?

60m
Find the diameter.

5 ft
Calculate the circumference. (units = km)

47.12km
What is the area of the tabletop?

7.065 ft2
The total amount of space inside of a circle

Area
What is the radius?

6.5 ft
What's the diameter?

13 ft

496.12 inches
The diameter of the pizza is 30 cm, what is the area?

706.5 cm2
What is the number we use for Pi?

What is the radius?

1.27 m
Find the diameter.

4.22 mm
The diameter of the playground is 194.68 feet. What is the circumference?

118,909.16 ft
What's the area?

239.86 in2