Question 1

Name the part of the circle indicated by the arrow.

Select the correct answer from the list below:

A: Tangent

B: Chord

C: Normal

D: Arc

CORRECT ANSWER: A: Tangent

WORKED SOLUTION:

Tangents are lines which touches the circumference of a circle at a single point.

Question 2

Name the part of the circle indicated by the arrow.

Select the correct answer from the list below:

A: Sector

B: Segment

C: Chord

D: Tangent

CORRECT ANSWER:   A: Sector

WORKED SOLUTION:

A sector of a circle is the area formed by two radii and an arc (also, is a fraction of the total area).

Question 3

Name the part of the circle indicated by the arrow.

Select the correct answer from the list below:

A: Tangent

B: Arc

C: Diameter

D: Sector

CORRECT ANSWER:  C: Diameter

WORKED SOLUTION:

The diameter of a circle is any line which touches the circumference at two points and passes through the centre.

Question 4

Calculate the area of the circle below to 1 decimal place:

The circle has a diameter of 4.1 cm.

Select the correct answer from the list below:

A: 13.2cm^2

B: 19.2cm^2

C: 8.6cm^2

D: 11.6cm^2

CORRECT ANSWER:  

WORKED SOLUTION:

The area of a circle is given by the formula, Area = \pi r^2

As the diameter of the circle is 4.1cm then the radius is 2.05cm.

Area = \pi\times2.05^2=13.2 cm^2

Question 5

Calculate the circumference of the circle below:

The circle has a radius of 8 cm.

Select the correct answer from the list below:

A: 45.7 cm

B: 55.0 cm

C: 38.5 cm

D: 50.3 cm

 

CORRECT ANSWER:  D: 50.3 cm

WORKED SOLUTION:

The circumference of a circle is given by the formula, circumference = \pi\times D= 2\pi\times r

As the radius of the circle is 8cm then the diameter is 16cm.

Circumference = 16\times\pi = 50.3 cm

Question 6

Calculate the perimeter of the half circle below:

The circle has a radius of 12 cm.

Select the correct answer from the list below:

A: 37.7 cm

B: 61.7 cm

C: 54.7 cm

D: 71.7 cm

CORRECT ANSWER:  B: 61.7 cm

WORKED SOLUTION:

Firstly we can calculate the perimeter of the arc by finding the circumference of the semi-circle

Circumference = (24\times\pi)\div2 = 37.7 cm

Now the base which is just the diameter of the circle can be added to find the total perimeter.

perimeter = 37.7+24 = 61.7 cm

Question 7

Calculate the area of the circle below:

The circle has a radius of 5 cm.

Select the correct answer from the list below:

A: 25.5 cm^2

B: 52.5 cm^2

C: 78.5 cm^2

D: 84.5 cm^2

CORRECT ANSWER:  C: 78.5 cm^2

WORKED SOLUTION:

The area of a circle is given by the formula, Area = \pi r^2

As the radius is 5cm then,

Area = \pi\times 5^2=78.5 cm^2