Student Resource Book |
Year 7 (4A)
Measurement & Geometry
Chapter 14 | Angles
Overview & Teacher Resource Sheets
Overview of the chapter
NOTE:YouTube has some good videos on angles. Search “angles in everyday life”.
Rich tasks
- These are problem solving open-ended questions that require students to name, measure and draw angles in contextual situations.
- These can be given at the start of a topic and done as the students gain enough knowledge to complete them, inserted into a topic at an appropriate place or given as homework or extension.
- Angle art
- Angles in real life
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1. Angle art
- This could be used as an introduction to different types of angles. Students could describe the angles in their drawings and the descriptions could then be categorised into specific types.
- Students could be asked to measure the angles in each other’s drawings as a check.
- To incorporate drawing specific angles in to this task you could ask students to draw something which includes angles of these sizes: 30°, 55°, 90°, 124°, 250° or choose some of your own.
- Once students have completed their drawings, you could use them to teach about the different types of angles and how to measure them.
2. Angles in real life
- Students could be challenged to display their findings and the results of their research in an interesting way.
- Students could work in groups and present their findings to the rest of the class. Encourage students to do more than just put outlines of angles on pictures and measure them.
Angles
- Recognise acute, right, obtuse, straight and reflex angles in diagrams and real life.
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Teaching ideas
Teacher notes
- Students often confuse obtuse and reflex angles. It helps to point out that the outside of the knee is a reflex angle and this is where a doctor might test your reflexes if you were ill by tapping the outside of the knee.
What is the angle?
- Estimate and/or recognise the angles that real life objects turn through.
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Teaching ideas
Clock angles
- Show a clock that has movable hands to the group/class. Discuss the approximate or actual angles between the hands at times such as 6 o’clock, 1/4 past 12 (this will not be an exact right angle because the small hand will have moved 1/4 way towards the 1 but it is almost a right angle). Discuss through what angle the big hand moves for various times.
Classroom angles
- Ask students to estimate the angle that the door turns through as you demonstrate, the angle that lids turn through, arms turn through and so on, demonstrating using things in the classroom.
- You could divide the class into groups and allocate points for correct answers.
- You could get groups to find angles for other groups to estimate.
Teacher notes
- Students will most likely be able to answer these questions well if they have been given a lot of examples of angles in every day life in the past. If they experience difficulty, spend some time asking more questions about examples of angles around us.
Measuring and drawing angles
- Estimate and measure the sizes of angles using a protractor.
- Practise at drawing angles using a protractor.
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Teaching ideas
Angle Jigsaw (Teacher resource sheet 28)
This link displays a puzzle for you to print, cut up and hand out to groups of students. You could give one jigsaw between two.
Ask students to measure the angles and put the pieces back together so that they match.
Teacher notes
- When the arm of an angle is not long enough to reach the scale on the protractor, put a ruler along the edge of the arm and read the scale where the ruler crosses it.
- It is important that students realize that a protractor has a clockwise and anticlockwise scale. Encourage students to estimate the size of the angle first. If they choose the wrong scale it will be immediately evident that their reading is not close to their estimate.
- Students sometimes put the protractor in the wrong place. Encourage them to check that the centre of the protractor is at the vertex (where the two arms meet) of the angle and that the bottom line of the protractor is along one arm.
Angle problems
- Find the sizes of missing angles using the facts that angles on a straight line add to 180° and angles at a point add to 360°.
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Teaching ideas
- Angles on a straight line and at a point
- Illustrate angles on a straight line, and around a point, by drawing a diagram using a ruler and asking students to come and measure the angles.
- Do this several times for angles on a straight line, and around a point, and ask students what they notice about the sum of the angles for each. You could get them to draw some diagrams of their own and measure the angles to see if they get similar results. Extend this by asking students if they could predict the size of the last angle to be measured in each diagram.
- You can show that two right angles, each measuring 90°, fitted together make a straight line and therefore they add to 180°. Point out that if we take 10° from one of the right angles and add it to the other to make a 100° angle and an 80° angle they still add to 180° and make a straight line. Extend this to taking 20°, 30° etc from one angle and adding it to the other.
- You can show that when you join four right angles, each measuring 90°, at a point they make a complete turn and add to 360°. Again, as with the straight line, you can show that subtracting an amount from one angle and adding it to another leaves the total of 360° unchanged.
Teacher notes
- Students should remember from their level 3 work that angles on a straight line add to 180° and that angles around a point add to 360°. They should also have met the fact that vertically opposite angles are equal.
