Circle calculations

Find the area of this circle. 

Take

 $\pi$  =3.142

•  $A=78.55\ cm^2$  

•  $A=70.63\ cm^2$  

•  $A=50.71\ cm^2$  

•  $A=80\ cm^2$  

What is the area of this semicircle ?
d = 8 cm

 Take

 $\pi$  =3.142

• 50.272 cm²

• 80 cm²

• 200.9 cm²

• 25.1 cm²

What is the formula to find the area of a circle?

• πr²

• 2πr

• √π

• π2r

What is the formula to find the circumference of a circle?

• πr²

• 2√π

• 
  

  $\pi d$

• √π

Work out the perimeter.

 $\pi$  =3.142

• 20.568 cm

• 12.562 cm

• 30 cm

• 20 cm

Find the circumference.

Take

 $\pi$  =3.142

• 60.4 cm

• 40 cm

• 62.8 cm

• 55.6 cm

If the diameter of a circle is d=28 cm. What is its radius

• r=10 cm

• r=14 cm

• r=13.5 cm

• r=28 cm

Find the perimeter of this shape. (

 $\pi=3.142$  

• 14 m

• 193.444 m

• 16.777 m

• 191.988 m

Is the red line a radius or diameter of the circle?

• Radius

• Diameter

Find the area of this shape.

• A=500 cm²

• A=258 cm²

• A=745.469 cm²

• A=245.3 cm²