A pair of compasses is a tool which can be used to draw circles and arcs. A pair of compasses is sometimes referred to just as a compass.

Checking compass skills

Maths

Securing the skill of using a pair of compasses

Understanding constructing a circle

Constructing triangles

Constructing rhombi

Diagonals of a rhombus

Bisecting an angle

Perpendicular bisector of a line segment

Perpendicular to a given line through a given point

Problem solving with constructions

The constructions covered in this unit are built on in the future unit. In the future unit, pupils construct triangles and construct diagrams following specific restrictions.

The prior unit gave pupils the opportunity to explore polygons and begin to generalise their understanding of interior/exterior angles in regular polygons. In this unit, pupils will use the geometrical properties of a rhombus to perform various constructions. 

In this unit we develop skills in using a pair of compasses and ruler to construct various accurate shapes and angles including triangles, rhombi, perpendicular lines and angle bisectors.

Constructions

The image shows a pencil inside a pair of {{ }}.

When drawing a circle with a pair of compasses, where is the needle once the circle is complete?

An {{ }} of a circle is part of the circle’s circumference.

Which one of these images is not a correct way to hold a pair of compasses while drawing a circle or arc?

Which part of a circle can be drawn by using a pair of compasses and rotating the pencil around the needle?

Aisha is about to use the pair of compasses to draw a circle. Which statement will be true, once it is drawn?

A {{ }} is a shape such that every point on the circumference is equidistant to its centre.

any line segment that joins the centre of a circle to its edge

any line segment that joins one edge of a circle with another

the furthest distance from one side of a circle to another

In which image is the circumference labelled with a question mark?

The ruler measures in cm. How long is the radius of the circle?

The diameter of a circle is 12 cm. Its radius is {{ }} cm.

Checking compass skills

Lesson outcome