Circumference and Area of Circles

Which formula is the correct one for calculating the circumference of a circle?

• $C=\pi r$

• $C=\pi D$

• $C=\pi r^2$

• $C=\pi D^2$

If the diameter of a circle is 6 cm, how do you calculate the circumference?

• $\pi\times6$

• $\pi\times12$

• $\pi\times3$

• $\pi\times3^2$

If the radius of a circle is 6cm, how do you calculate the circumference?

• $\pi\times6$

• $\pi\times12$

• $\pi\times3$

• $\pi\times3^2$

• A

• B

• C

• D

• A

• B

• C

• D

• A

• B

• C

• D

Which formula is the correct one for finding the area of a circle?

• $A=\pi r$

• $A=\pi D$

• $A=\pi r^2$

• $A=\pi D^2$

If the radius of a circle is 6cm, what is the correct calculation to find the area?

•  $\pi\times6$  

•  $\pi\times12$  

•  $\pi\times6^2$  

•  $\pi\times3^2$  

If the diameter of a circle is 6cm, what is the correct calculation to find the area?

• $\pi\times6$

• $\pi\times12$

• $\pi\times6^2$

• $\pi\times3^2$

• A

• B

• C

• D