Circumference and Area

Terms

100

The middle of a circle is called what?

Center

200

What is circumference?

Distance around a circle.

300

What is a diameter?

Distance across the circle through the center.

400

What is the radius?

A line from the center to the any point in the circle

500

What is area?

Space inside a closed shape.

Formulas

100

What is the formula of diameter?

d=2r

200

How much is pi?

3.14

300

What is the formula for circumference you use if given the diameter?

C=(pi)d

400

What is the formula for circumference you use if given the radius?

C=2(pi)r

500

What is the formula for area?

A=(pi)r^2

Circumference

100

Diameter is 10. What is the circumference?

C=31.4

200

Diameter is 52. What is the circumference?

C=163.28

300

Radius is 4. What is the circumference?

C=25.12

400

Radius is 6.2. What is the circumference?

C=38.936

500

Circumference is 42.8 What is the radius?

Round to the tenths. 

C=6.82

Area

100

Diameter is 2. What is the area?

A=3.14

200

Radius is 3. What is the area?

A=28.26

300

Radius is 9. What is the area?

A=254.34

400

Radius is 12. What is the circumference? 

A=452.16

500

Diameter is 8. What is the area?

A=200.96

Random

100

R=2

D=?

C=?

R=2

D=4

C= 12.56

200

R=6

D=?

C=?

R=6

D=12

C=37.68

300

Label the formula for AREA.

A=AREA

(PI)=3.14

R=RADIUS

^2=SQUARED (EXPONET)

400

Label the formula for CIRCUMFERENCE. (IF GIVEN THE DIAMETER.)

C=CIRCUMFERENCE

PI=3.14

D=DIAMETER

500

Find the radius. C=43

C=6.85