Find unknown angles in triangles

In this lesson, we will represent the angles in a triangle pictorially and algebraically before learning how to calculate missing angles.

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.What shape is being described below?

1/5

Q2.Select the correct description of a trapezium.

2/5

Q3.The interior angles in a quadrilateral add up to:

3/5

Q4.What is the value of the missing angle?

4/5

Q5.If a parallelogram has a perimeter of 6cm, what are the lengths of the sides?

5/5

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Intro quiz - Recap from previous lesson

Before we start this lesson, let’s see what you can remember from this topic. Here’s a quick quiz!

Q1.What shape is being described below?

1/5

Q2.Select the correct description of a trapezium.

2/5

Q3.The interior angles in a quadrilateral add up to:

3/5

Q4.What is the value of the missing angle?

4/5

Q5.If a parallelogram has a perimeter of 6cm, what are the lengths of the sides?

5/5

Video

Play video

Click on the play button to start the video. If your teacher asks you to pause the video and look at the worksheet you should:

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Worksheet

These slides will take you through some tasks for the lesson. If you need to re-play the video, click the ‘Resume Video’ icon. If you are asked to add answers to the slides, first download or print out the worksheet. Once you have finished all the tasks, click ‘Next’ below.

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Find the value of missing angles in triangles - Quiz

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.What is the value of angle a?

1/3

Q2.What is the value of angle a?

2/3

Q3.What is the value of angle y?

3/3

This quiz includes images that don't have any alt text - please contact your teacher who should be able to help you with an audio description.

Quiz:

Find the value of missing angles in triangles - Quiz

Don’t worry if you get a question wrong! Forgetting is an important step in learning. We will recap next lesson.

Q1.What is the value of angle a?

1/3

Q2.What is the value of angle a?

2/3

Q3.What is the value of angle y?

3/3

Lesson summary: Find unknown angles in triangles

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