Support your pupils in reasoning with shape properties using this Year 5 calculating angles worksheet. The first activity requires children to complete a table listing common 2D shapes, the number of angles each has and their total internal angles. Some data points are pre-filled (e.g. pentagon = 540°, octagon = 1080°), guiding learners to apply rules such as (number of sides − 2) × 180 to complete the rest. In the second section, children use their completed table to calculate the size of each interior angle in regular polygons, including the square, hexagon and equilateral triangle. This KS2 resource builds understanding of angle rules and shape reasoning.
Key Curriculum Focus
This KS2 geometry worksheet aligns with the national curriculum by supporting:
- Calculating angles in regular polygons using known geometric rules
- Understanding and using properties of shapes to reason mathematically
- Solving problems involving angles, including calculating unknown values
Pupils learn to apply a formula to find a polygon’s total internal angle sum, then divide by the number of angles to find the size of each angle in a regular shape. The Year 5 calculating angles worksheet strengthens reasoning and helps children connect number patterns to geometric structure, building confidence with angle calculation in KS2.
Calculating Angles in Year 5 Maths
The total angle sum of a polygon can be found using the formula (number of sides − 2) × 180°. For example, a hexagon has 6 sides, so the total internal angle sum is (6 − 2) × 180 = 720°. In a regular hexagon, all angles are equal, so each one measures 720 ÷ 6 = 120°. In Year 5, children begin using these strategies to calculate unknown angles and recognise patterns between different shapes, enhancing their understanding of geometry.
Activity Idea: Polygon Posters
Ask children to create a mini-poster showing five regular polygons. They should include the name, number of sides, total angle sum and one calculation showing how they found the size of each angle. Display the posters as part of a class maths display to reinforce learning and provide reference visuals.
Check out more Year 5 maths resources
Support your class in applying known geometry facts with this Year 5 Angle Rules Worksheet. Children calculate missing angles using properties of straight lines, right angles and vertically opposite angles. To build on this topic further, take a look through our complete range of Year 5 maths worksheets designed to help KS2 learners reason mathematically using shape and angle relationships.
