Working out angles III 0 Overview Using this Resource Connecting to the Curriculum Marking Student Responses Working with Students Further Resources This task is about working out angles from known properties of interior angles of shapes. Question 1Change answer a) Work out the size of angles x and y for the diagram above. a) Work out the size of angles x and y for the diagram above. x = degrees y = degrees Question 1Change answer b) Work out the size of angles x and y for the diagram above. b) Work out the size of angles x and y for the diagram above. x = degrees y = degrees Question 1Change answer c) Work out the size of angles x and y for the diagram above. c) Work out the size of angles x and y for the diagram above. x = degrees y = degrees Question 1Change answer d) Work out the size of angles x and y for the diagram above. d) Work out the size of angles x and y for the diagram above. x = degrees y = degrees Task administration: This task can be completed with pencil and paper or online (with auto marking displayed to students). Level: 5 Curriculum info: Maths, Geometry and Measurement, Shape Keywords: angles, interior angles, circles, diameter, triangles Description of task: Students use the angle-in-a-semicircle property, and the sum of the angles in a triangle to find unknown angles. Learning Progression FrameworksThis resource can provide evidence of learning associated with Geometric thinking, set 6 within the Mathematics Learning Progressions Frameworks.Read more about the Learning Progressions Frameworks. Answers/responses: Y10 (10/1998) a) i) ii) 90 65 difficult difficult b) i) ii) 55 55 difficult difficult c) i) ii) 100 30 very difficult very difficult d) i) ii) 50 80 very difficult very difficult Diagnostic and formative information: Common error Likely calculation Likely reason a) i) ii) 77.5 77.5 (180 - 25) ÷ 2 (180 - 25) ÷ 2 Sees triangles as isosceles. c) i) ii) d) i) ii) 95 approx. 40 approx. 55 approx. 70 approx. Measures angles with a protractor. (May indicate a) and b) are measured by a protractor too). Working out angles Sum of the angles Working out angles II Street angles Angles of an octagon Angles of a hexagon Inside a triangular prism Inside a cube Inside a rectangular prism