Year 5 - Maths
Describe static angles using the standard unit of degrees when compared to a right angle
Angles: compare, name, estimate and measure angles
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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 pupils will compare the size of angles where there is a clear visual difference and use the terms acute, obtuse and reflex when describing the size of angles or amount of rotation with relation to right angles using a unit called degrees.
Lesson Summary
You will learn to describe static angles using the standard unit of degrees when compared to a right angle.
Key Notes
- There are 90 degrees in a right angle
- Acute angles are between 0 and 90 degrees
- Obtuse angles are between 90 and 180 degrees
- Reflex angles are greater than 180 degrees
Vocabulary To Learn
- Degrees: A degree is a unit of measure for angles.
- Estimate: To estimate is to find a value that is close enough to the right answer, usually with some thought or calculation involved.
Common Mistakes To Avoid
- 90 degrees is classified as an acute angle and 180 degrees is classified as an obtuse angle.
3 Quick Questions (With Answers)
1. Solve this in steps: explain the method from this lesson and why each step matters.
There are 90 degrees in a right angle. Acute angles are between 0 and 90 degrees.
2. Use this key word in a maths sentence and explain it clearly. 'Degrees'
A degree is a unit of measure for angles. Use this word when showing your method, then check your final answer is reasonable.
3. Spot and fix this common maths mistake.
Mistake: 90 degrees is classified as an acute angle and 180 degrees is classified as an obtuse angle. Correction: Provide opportunities for pupils to classify angle sizes and build towards understanding that acute angles are between 0-89 degrees and obtuse angles are between 91-179 degrees. Classifying multiples of right angles as a separate group may help.
More Lessons In This Unit
- Angles in quadrilaterals Study Guide
- Angles in triangles Study Guide
- Describe rotations using the standard unit of degrees when compared to a right angle Study Guide
- Draw angles accurately using a protractor Study Guide
- Estimate acute and obtuse angles using the standard unit of degrees Study Guide
- Know that the angles at a point sum to 360 degrees and use this to solve problems Study Guide
- Know that the angles in a full turn sum to 360 degrees and use this to solve problems Study Guide
- Know that the angles on a straight line sum to 180 degrees and use this to solve problems Study Guide
- Measure the size of angles accurately using a protractor Study Guide
- Reasoning about angles in polygons Study Guide
- Review understanding and identification of right angles Study Guide
- Review understanding of angles as a measure of turn Study Guide
- Use the terms acute, obtuse and reflex when comparing angles to a right angle Study Guide
- Use the unit of degrees as a standard unit to measure angles Study Guide
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