Circles: Radius, Diameter, and Circumference

Circle Terms

100

What is the definition of radius?

The distance from the center of a circle to the outside, also half of the diameter

200

What is the definition of diameter?

The distance across a circle through the center

300

What are the two formulas to find the Circumference of a circle?

C= d(pi)

C= 2r(pi)

400

What is the definition of area? Find the formula for the area of a circle

The total amount of space inside of a circle

A= pi (r²) 

500

What does pi equal? (Both decimal and fraction form)

3.14 and 22/7

Finding Radius(find the radius for all)

100

The diameter of this circle is 9, the radius is...

4.5

200

The diameter is the circle is 21, the radius is...

10.5

300

The circumference of the circle is 50.24, the radius is...

8

400

The diameter of this circle is 437, the radius is...

218.5

500

The area of the circle is 50.24, the radius is...

4

Finding Diameter (Find Diameter for all)

100

The radius of the circle is 5, the diameter is...

10

200

The radius of the circle is 2.5, the diameter is...

5

300

The circumference of the circle is 15.7, the diameter is...

5

400

The circumference of this circle is 18.84, the diameter is...

6

500

The circumference of the circle is 194.68, the diameter is...

62

Finding Circumference(Find Circumference for all)

100

The diameter for the circle is 10 the circumference is...

31.4

200

The diameter for the circle is 13 the circumference is...

40.82

300

The diameter of the circle is 25, the circumference is...

78.5

400

The radius for the circle is 45, the circumference is...

282.6

500

The Diameter for this circle is 3285

What is 10314.9

Finding Area(Find area for all)

100

The radius of the circle is 2, the area is...

12.56

200

The radius of the circle is 3, the area is...

28.26

300

The radius of the circle is 21, the area is...

1384.74

400

The radius of the circle is 13, the area is...

530.66

500

The diameter of the circle is 51, the area is...

1,319.59