Circles: Radius, Diameter, and Circumference

Circle Terms

100

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

What is radius

200

The line from end to end through the center of the circle 

What is the Diameter

300

3.14 x d

What is the circumference formula?

400

3.14 x r x r 

What is the area formula?

500

(3.14 x r x r ) divided by 2 

What the area of a semi-circle?

Finding Radius(find the radius for all)

100

The Diameter of this circle is 5 in

What is 2.5in

200

The circumference of a circle is 31.4 ft

What is 5 ft?

300

The circumference of a circle is 20.724 cm

What is 3.3 cm

400

The circumference of a circle is 21.352 yd

What is 3.4 yd?

500

The area of a circle is 28.26 m²

What is 3 m?

Finding Diameter (Find Diameter for all)

100

The radius of this is 5 ft

What is 10 ft

200

The circumference of this circle is 15.7 in

What is 5 in

300

The circumference of a circle is 18.84 cm

What is 6 cm

400

The circumference of a semi circle is 12.56 ft

What is 8 ft

500

The area of a circle is 78.5 in²

What is 10 in

Finding Circumference(Find Circumference for all)

100

The diameter for this circle is 10 ft

What is 31.4 ft

200

The radius is 13 in

81.64 in

300

The radius of a circle is 2.8 cm

What is 17.584 cm

400

The area of a circle is 28.26 mm²

What is 18.84 mm

500

The area of a circle is 254.34 mm²

What is 56.52 mm

Finding Area(Find area for all)

100

The radius of this circle is 2 ft

What is 12.56ft²

200

The diameter of a circle is 13 in

What is 176.63in² 

300

The diameter of a circle is 7cm

What is 38.465 cm²?

400

The circumference is 30in

What is 72.3in²?

500

The circumference of circle is 23.55 m

What is 44.2m²