Circle Terms
Finding Radius & Diameter
Formulas
(What would you put in the calculator to solve)
Finding Circumference
(Find Circumference for all)
Finding Area
(Find area for all)
100
The distance from the center of a circle to the outside, also half of the diameter
What is radius
100
The Diameter of this circle is 5
What is 2.5
100

Formula for circumference

What is πd

100
The diameter for this circle is 10
What is 31.4
100
The radius of this circle is 2
What is 12.56
200

The longest line in a circle

What is the Diameter

200

The radius of this circle is 2.5

What is 5

200

Formula for area

What is πr2

200
The diameter for this circle is 13
What is 40.82
200
The radius of this circle is 3
What is 28.26
300

What the diameter passes through and the radius meets

What is the center

300

The circumference of this circle is 194.68. Find the diameter.

What is 62

300

The circumference is 37.68 and the diameter is 12.

What is π(12) 

[or 3.14(12)]

300
The diameter of this circle is 25
What is 78.5
300

The radius of this circle is 21

What is 1384.74

400
The total amount of space inside of a circle
What is the area?
400

The circumference of this circle is 15.7. Find the radius.

What is 2.5

400

The area is 78.5 and the radius is 5

What is π(5)2

[or 3.14(5)2]

400
The radius for this circle is 45
What is 282.6
400
The radius of this circle is 52.4
What is 8621.6864
500
3.14 or 22/7
What is pi?
500

The circumference of this circle is 18.84. Find the radius.

What is 3

500
The circumference of this circle is 75.36 and the radius is 12.

What is π(24) 

[or 3.14(24)] 

500
The Diameter for this circle is 3285
What is 10314.9
500
The radius of this circle is 6955
What is 151888158.5
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