Loading please wait

The smart way to improve grades

Comprehensive & curriculum aligned

Try an activity or get started for free

Calculate Missing Angles in Quadrilaterals

In this worksheet, students will calculate missing angles in quadrilaterals.

'Calculate Missing Angles in Quadrilaterals' worksheet

Key stage:  KS 3

Year:  Year 8 Maths worksheets

Curriculum topic:   Geometry and Measures

Curriculum subtopic:   Derive/Use the Sum of Angles for Deduction

Difficulty level:  

Worksheet Overview

In this activity, we will find missing angles in quadrilaterals.


Quadrilaterals have four sides and four angles!


The total of all the angles in a triangle is 180o


a triangle


As a quadrilateral is made up of two triangles, the angles in a quadrilateral add up to 180 + 180 = 360


quadrilateral split into two triangles


How would we use this in a question?


Let's try one .......



Find the missing angle A in the quadrilateral.


angles in a quadrilateral



To find angle A, we add up the existing angles and subtract this from 360°.

A = 360 - (70 + 120 + 65)

A = 360 -  255

A  = 105°


Does that make sense?


woman thinking


Let's have a go at some questions.

What is EdPlace?

We're your National Curriculum aligned online education content provider helping each child succeed in English, maths and science from year 1 to GCSE. With an EdPlace account you’ll be able to track and measure progress, helping each child achieve their best. We build confidence and attainment by personalising each child’s learning at a level that suits them.

Get started

Try an activity or get started for free

  • National Tutoring Awards 2023 Shortlisted / Parents
    National Tutoring Awards 2023 Shortlisted
  • Private-Tutoring-WINNER-EducationInvestor-Awards / Parents
    Winner - Private Tutoring
  • Bett Awards Finalist / Parents
  • Winner - Best for Home Learning / Parents
    Winner - Best for Home Learning / Parents