Calculating angles 1 Jacob is calculating the size of a missing angle. Copy and complete his working. 120° Q1 hint a Angles on a straight line add up to u °. 120 ° + u = 180 ° a = u ° 120 130 140 150 160 2 Work out the missing angles. Explain your reason. a b 70 180 c 38° 101° a 52° b c 3 Copy and complete the calculation for the first angle. Work out the next two in the same way. a b x Q3a hint c 38° z 43° 295 300 y 295° 295 ° + u = 360 ° x=u Angles at a point add up to u °. Enrichment 5 y axis 1 On squared paper plot the points A = (2, 3), B = (0, 5) and C = (4, 5). Join A to B to C. ^C? What kind of angle is AB 4 3 2 1 0 1 2 3 4 x axis 5 2 Reasoning / Problem-solving Six friends share a circular pizza equally. What angle is each slice? Reflect 3 How many pairs of parallel sides does a regular hexagon have? Does it have any perpendicular sides? 189 4 Reflect Which of these tasks is the easiest? Which of these tasks is the hardest? A Naming angles (like in Types of angles and lines, Q1, Q2 and Q3). B Measuring angles (like in Estimating, measuring and drawing angles, Q5). C Drawing angles (like in Estimating, measuring and drawing angles, Q9). D Working out missing angles (like in Calculating angles, Q2 and Q3). Discuss with a classmate the thing you found hardest. Why is it hard? Ask your classmate for tips on how to make this task easier. 360