1. Shape and Space DEGREE

2. DEGREE We use degrees (e.g. 90°) to measure angles Right Angle (90°) Straight Line (180°) Full Turn (360 °) Acute Angle (less than 90°) Obtuse Angle (less than 180°, more than 90°) Reflex Angle (less than 360°, more than 180°)

3. EXERCISES Describe the following as: a) Right Angle b) Straight Line c) Acute Angle d) Obtuse Angle e) Reflex Angle 3) 4) 5) 6) 7) 8) 9) 10) 11) 1) 2)

4. MEASURING ANGLES We use a PROTRACTOR to measure angles. A protractor has a clockwise and anticlockwise scale If an angle turns (opens) clockwise you must use the external scale If an angle turns (opens) anticlockwise you must use the internal scale

5. MEASURING ANGLES Step 1: Put the centre of the protractor on the corner of the angle Step 2: Turn the protractor so that 0° is on one of the lines Step 3: Start to count in the direction of the angle 10°, 20°, 30° etc 10° 20° 30° 50° 40° 70° 60° 0°0° Cwblhewch y taflenni gwaith Complete the worksheets

6. CREATING A 70° ANGLE Step 1: Put the centre of the protractor on the end of a straight line Step 2: Turn the protractor so that 0° is on the line Step 3: Start to count in the direction of the angle 10°, 20°, 30° etc Step 4: Put a dot on 70° Step 5: Connect the dot with the end of the straight line 10° 20° 30° 50° 40° 70° 60° 0°0° 70°

7. EXERCISES Using a Protractor and Ruler, create these angles in your books. Label each angle like this :- a)60° b)45° c)130° d)145° e)75° f)105° g)57° h)168° i)23° 35°

8. STRAIGHT LINE (180°) We don’t always find angles by measuring. We can calculate angles. Angles on a straight line add to 180° 80° a a = 180° – 80° a = 100° 162° b b = 180° – 162° b = 18°

9. EXERCISES Calculate the angles labelled with letters 50° a 138° c b 65° d 117° 72° e 103° f 30° g 20° 50° h 100° i 64°

10. FULL TURN (360°) We don’t always find angles by measuring. We can calculate angles. Angles around a point make a full turn. They add to make a total of 360° 290° a 235° b a = 360° – 290° a = 70° b = 360° – 235° b = 125°

11. EXERCISES Calculate the angles labelled with letters 285° a 82° b c 32° d 24° 130° e 170° 147° f g 156° 44° h 88° 134°

12. OPPOSITE We don’t always find angles by measuring. We can calculate angles The OPPOSITE angles are equal. This happens when two lines cross each other. One RED ANGLE and one BLUE ANGLE add to 180° 120° 60° q p 150° x z y q = 60° p = 120° y = 150° x = 30° z = 30°

13. EXERCISES Calculate the angles labelled with letters a 40° 135° b c d 145° 35° 29° 151° f e 40° i g h 150° k L j 35° m n o 77° p q r t u s