130 likes | 184 Views
Shape and Space. DEGREE. DEGREE. We use degrees (e.g. 90 °) to measure angles. Full Turn (360 °). Right Angle (90 °). Straight Line (180 °). Reflex Angle (less than 360 °, more than 180°). Obtuse Angle (less than 180°, more than 90°). Acute Angle (less than 90 °). 3). 2). 4).
E N D
Shape and Space DEGREE
DEGREE • We use degrees(e.g. 90°) to measure angles Full Turn (360 °) Right Angle (90°) Straight Line (180°) Reflex Angle (less than 360°, more than 180°) Obtuse Angle (less than 180°, more than 90°) Acute Angle (less than 90°)
3) 2) 4) 1) 7) 8) 6) 5) 9) 11) 10) EXERCISES • Describe the following as: • a) Right Angle b) Straight Line c) Acute Angle d) Obtuse Angle e) Reflex Angle
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
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 70° 60° 50° 40° 30° 20° 10° 0° Cwblhewch y taflenni gwaith Complete the worksheets
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 70° 60° 50° 40° 30° 70° 20° 10° 0°
Using a Protractor and Ruler, create these angles in your books. Label each angle like this :- 35° EXERCISES • 60° • 45° • 130° • 145° • 75° • 105° • 57° • 168° • 23°
a 162° 80° b STRAIGHT LINE (180°) • We don’t always find angles by measuring. We can calculate angles. • Angles on a straight line add to 180° b = 180° – 162° b = 18° a = 180° – 80° a = 100°
138° a b c 65° 50° f 117° 103° e 72° d 64° 50° g 30° 100° h 20° i EXERCISES • Calculate the angles labelled with letters
a b 290° 235° 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° a = 360° – 290° a = 70° b = 360° – 235° b = 125°
c 24° d 82° 32° a b 285° e 156° h f 44° 130° 170° 88° g 147° 134° EXERCISES • Calculate the angles labelled with letters
150° 120° x z q 60° y p 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° y = 150° x = 30° z = 30° q = 60° p = 120°
135° 145° 35° a 40° c d b f e g 29° 150° 151° 40° j L h i k 35° r s o n p 77° t q m u EXERCISES • Calculate the angles labelled with letters