Calculate the Angle Sum of a Triangle

Did you know you can work out the interior angle size of any regular polygon using triangles? You just need to remember one fact – that the angle sum of a triangle is 180°.

This worksheet provides students with the opportunity to practise calculating the size of the missing angles in a variety of triangles, based on the knowledge that the angle sum of a triangle is 180°.

An answer key is included with your download to make marking fast and easy!

Tips for Differentiation + Scaffolding 

In addition to independent student work time, use this worksheet as an activity for:

• Whole-class review (via smartboard)
• Guided maths groups
• Independent practice
• Homework assignment
• Summative assessment

Some students may need a reminder of the angle sum of a triangle when completing the worksheet. Our Angle Sum of a Triangle Poster is the perfect resource to paste into your students’ workbooks as a visual guide to refer back to while completing the worksheet.

Download This Printable Angles Worksheet

Use the Download button to access the easy-print black-and-white PDF.

Because this resource includes an answer sheet, we recommend you print one copy of the entire file, then make photocopies of the blank worksheet for students to complete. 

Looking for a more sustainable way to use this resource? Project the worksheet onto a screen and work through it as a class by having students record their answers in their workbooks.

Click below for more time-saving angles resources to cut down on your planning time!

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