Year 8 - Maths
Understanding constructing a circle
Constructions
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This pupil-friendly study guide includes a unit summary, clear notes, common mistakes, and quick questions with answers.
Unit Summary
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.
Lesson Summary
You will learn to recognise a circle as a collection of points equidistant from a fixed point.
Key Notes
- A pair of compasses can be used to draw circle with a particular radius.
- All the points on the circle will be the same distance from the centre.
- The centre of a circle is the point that is the same distance from every point on the circle.
- The collection of points an equal distance from a given point form a circle.
Vocabulary To Learn
- Fixed point: A fixed point is a point that does not change or move.
- Circumference: The circumference of a circle is the perimeter of the circle.
- Arc: An arc is part of a curve. An arc of a circle is part of the circle's circumference.
- Equidistant: Points A and B are equidistant from a third point C if the distance AC is equal to the distance BC.
Common Mistakes To Avoid
- During tasks, pupils may use a ruler to draw or check whether points are equidistant from a centre.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
A pair of compasses can be used to draw circle with a particular radius. All the points on the circle will be the same distance from the centre.
2. Use this key word in a maths sentence and explain it clearly. 'Fixed point'
A fixed point is a point that does not change or move. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: During tasks, pupils may use a ruler to draw or check whether points are equidistant from a centre. Correction: While the tasks could be completed with a ruler, it may be quicker, easier and more accurate to use a pair of compasses.
More Lessons In This Unit
- Bisecting an angle Study Guide
- Checking compass skills Study Guide
- Constructing rhombi Study Guide
- Constructing triangles Study Guide
- Diagonals of a rhombus Study Guide
- Perpendicular bisector of a line segment Study Guide
- Perpendicular to a given line through a given point Study Guide
- Problem solving with constructions Study Guide
- Securing the skill of using a pair of compasses Study Guide
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