Year 8 - Maths
Securing the skill of using a pair of compasses
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 use a pair of compasses to draw different circles.
Key Notes
- A pair of compasses can be used to draw a circle with a particular radius.
- A pair of compasses can be used to draw two circles that intersect.
- A pair of compasses can be used to draw two circles that only intersect once.
Vocabulary To Learn
- Radius: The radius is any line segment that joins the centre of a circle to its edge.
- Compass: 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.
Common Mistakes To Avoid
- Pupils may find it difficult to decide where to mark the centre point of each circle during Task A.
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 a circle with a particular radius. A pair of compasses can be used to draw two circles that intersect.
2. Use this key word in a maths sentence and explain it clearly. 'Radius'
The radius is any line segment that joins the centre of a circle to its edge. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: Pupils may find it difficult to decide where to mark the centre point of each circle during Task A. Correction: Pupils could start the task by drawing a pair of circles and labelling it with the question that presents the matching description.
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
- Understanding constructing a circle Study Guide
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