Working out angles

Working out angles

Auto-markingPencil and paperOnline interactive
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about working out unknown angles in different shapes.

Question 1Change answer

angles diagram a
This shape is a square.
What is the size in degrees, of the angle marked 'a'?  degrees

Question 1Change answer

angles diagram b
The marked sides of this triangle are equal in length.
What is the size in degrees, of the angle marked 'b'?  degrees

Question 1Change answer

angles diagram c
This shape is a parallelogram.
What is the size in degrees, of the angle marked 'c'?  degrees

Question 1Change answer

angles diagram d
This shape is a hexagon with equal sides.
What is the size in degrees, of the angle marked 'd'?  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: 
interior angles, polygons, parallelograms, isosceles
Description of task: 
Students use their knowledge of the interior angles of regular polygons, isosceles triangles, and parallelograms to work out unknown angles for a variety of 2-dimensional shapes.
Learning Progression Frameworks
This 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 (09/1998)
a) 90 very easy
b) 50 moderate
c) 108 moderate
e) 120 difficult
Diagnostic and formative information: 
  Common error Likely calculation Likely reason
b)
c)		 80
72		   Repeats the value of the given angle
b) 45 90 ÷ 2 Assumes the two angles sum to 90°
d) 60 360 ÷ 6 Gives the exterior angle rather than the interior angle