A chord is any line segment joining two points on the circumference of a circle.

Two segments are created when dividing a circle into two parts using a chord.

A sector is the region formed between two radii and their connecting arc.

An arc is part of a curve. An arc of a circle is part of the circle’s circumference.

Checking and securing understanding of circles

Maths

In this unit, pupils built upon their prior learning of the area of different shapes. In the future unit, pupils will continue to further develop their understanding of shapes by considering surface area and volume of pyramids, spheres and cones.

In the prior unit, pupils derived the formula for the circumference and area of a circle. In this unit, this knowledge is combined with knowledge of fractions to find the arc length and area of a sector.

2D and 3D shape: compound shapes

Each diagram shows a different part of a circle. Match each part of a circle to its name.

The length of the diameter of this circle is {{ }} inches.

The diameter of the circle is 150$$\pi$$ cm.

An arc from this circle must be less than or equal to 150 cm in length.

An arc from this circle must be greater than or equal to 150 cm in length.

The circumference of a circle is 150 cm.
Which of these statements is correct about the circle?

The circumference of the circle is 30$$\pi$$ cm.

The circumference of the circle is 60$$\pi$$ cm.

The circumference of the circle is 120$$\pi$$ cm.

The diameter of a circle is 60 cm.
Which of these statements is correct about the circle?

The area of the circle is 81$$\pi$$ cm².

The area of the circle is 255 cm² (to the nearest integer).

The radius of a circle is 9 cm.
Which of these statements is correct about the circle?

The area of this circle can be calculated from the equation $$A = \pi \times 62^2$$.
Match each property of the circle to its value.

It is made up of more than just straight-line segments.

Three of its line segments intersect at a perpendicular right-angle.

Which of these statements correctly explains why this shape is not a polygon?

1 centilitre equals $$1 \over 100$$ litres. 
Match each letter in the ratio table to its value to convert 4040 cl into litres.

The perimeter of this parallelogram is {{ }} cm.

The area of this parallelogram is {{ }} cm².

This lesson will soon be taken down.

Checking and securing understanding of circles

Lesson outcome