# Polygons and triangles

In this lesson, we will learn that the sum of the interior angles of a polygon can be found using triangles.

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
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.ABCD forms a quadrilateral. What are the total interior angles of the quadrilateral?

1/5

Q2.Angle ABC is 98 degrees. What would the size of the reflex angle formed be on the exterior?

2/5

Q3.If I combined two equilateral triangles together with a shared side, what would the shape formed be called?

3/5

Q4.Which of the following is not a rule used so far for angles?

4/5

Q5.If A + B + C = 180, D + E = 180 and F is a right angle, what does A + B + C + D + E + F equal?

5/5

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
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.ABCD forms a quadrilateral. What are the total interior angles of the quadrilateral?

1/5

Q2.Angle ABC is 98 degrees. What would the size of the reflex angle formed be on the exterior?

2/5

Q3.If I combined two equilateral triangles together with a shared side, what would the shape formed be called?

3/5

Q4.Which of the following is not a rule used so far for angles?

4/5

Q5.If A + B + C = 180, D + E = 180 and F is a right angle, what does A + B + C + D + E + F equal?

5/5

# 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:

• Click "Close Video"
• Click "Next" to view the activity

Your video will re-appear on the next page, and will stay paused in the right place.

# 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.

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Polygons and triangles

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

Q1.The total sum of the interior angles of two triangles would be equal to...

1/5

Q2.If I have a regular pentagon, how many triangles from one distinct point internally can I create?

2/5

Q3.If I have a regular pentagon, what would the total interior angles sum to?

3/5

Q4.If I have a regular octagon, how many triangles from one distinct point internally can I create?

4/5

Q5.If I have a regular octagon, what would the total interior angles sum to?

5/5

#### Unit quizzes are being retired in August 2023

Why we're removing unit quizzes from the website >
Quiz:

# Polygons and triangles

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

Q1.The total sum of the interior angles of two triangles would be equal to...

1/5

Q2.If I have a regular pentagon, how many triangles from one distinct point internally can I create?

2/5

Q3.If I have a regular pentagon, what would the total interior angles sum to?

3/5

Q4.If I have a regular octagon, how many triangles from one distinct point internally can I create?

4/5

Q5.If I have a regular octagon, what would the total interior angles sum to?

5/5

# Lesson summary: Polygons and triangles

## Time to move!

Did you know that exercise helps your concentration and ability to learn?

For 5 mins...

Move around:
Walk

On the spot:
Chair yoga