Circles - Area And Circumference

This lesson covers:

  1. What the terms 'circumference', 'radius', and 'diameter' mean
  2. How to calculate the area and circumference of a circle 

What does A represent in the diagram below?

Diagram of a circle labeled with A on the circumference, B representing the diameter, and C representing the radius.

Radius

Circumference 

Diameter

Hypotenuse

0

/

1

What does B represent in the diagram below?

Diagram showing a circle with labelled radius, diameter, and other segments.

Hypotenuse

Diameter

Radius

Circumference 

0

/

1

What does C represent in the diagram below?

Diagram of a circle with labelled parts A, B, and C.

Radius

Hypotenuse

Diameter

Circumference 

0

/

1

The circle below has a radius of 5 cm. Calculate the area of the circle.

(Give your answer to 3 significant figures)

Diagram of a circle with a radius of 5 cm.
78.5

cm2

cm2

0

/

1

The circle below has a radius of 3 cm. What is the diameter of the circle?

Diagram showing a circle with a radius of 3 cm.
6

cm

cm

0

/

1

The circle below has a radius of 6 m. What is the circumference of the circle?

Diagram of a circle with a radius of 6 meters.
37.7

m

m

0

/

1

The circle below has a diameter of 16 cm. Calculate the circumference of the circle.

(Give your answer to 3 significant figures)

Circle with a diameter of 16 cm
50.3

cm2

cm2

0

/

1

Calculate the area of the circle below.

(Give your answer to 3 significant figures)

Diagram of a circle with a 14 cm radius for calculating area.
616

cm2

cm2

0

/

1

Calculate the area of the circle below.

(Give your answer to 3 significant figures)

Diagram of a circle with a diameter of 12 cm.
113

cm2

cm2

0

/

1

Calculate the circumference of the circle below.

(Give your answer to 3 significant figures)

Diagram of a circle with a diameter of 12 cm.
37.7

cm2

cm2

0

/

1