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## Basic geometry and measurement

### Course: Basic geometry and measurement > Unit 4

Lesson 5: Lines of symmetry# Symmetry review

Review symmetrical shapes and lines of symmetry. Then, try some practice problems.

## Line of symmetry

A ${\text{line of symmetry}}$ is a line where we can fold the image and have both halves match exactly.

**Example:**

When we divide the figure with Line ${A}$ , the resulting two parts are mirror images of each other:

Line ${A}$ is a line of symmetry.

*Want to learn more about lines of symmetry? Check out this video.*

## Symmetrical figures

Shapes are ${\text{symmetrical}}$ if they have at least one ${\text{line of symmetry}}$ on them.

**Example:**

This shape is ${\text{symmetrical}}$ :

Because we can draw at least one ${\text{line of symmetry}}$ on it:

*Want to learn more about symmetrical figures? Check out this video.*

## Practice

*Want to try more problems like this? Check out these exercises:*

Identify lines of symmetry and symmetrical figures

Draw lines of symmetry and symmetrical figures

## Want to join the conversation?

- How many lines of symmetry does a circle have(49 votes)
- Circles have an infinite amount of lines of symmetry. You can go on and on and on and never find a specific number of lines of symmetry. Circles are the only figures that have an infinite amount of lines of symmetry.(114 votes)

- how many lines of symmetry does a circle have(20 votes)
- A circle has infinite lines of symmetry(19 votes)

- I did not understand how the pentagon had symmetry that way can you help me please?(14 votes)
- Yes, if you fold the pentagon over the dotted line, then the two pieces would match perfectly.(13 votes)

- how to find total number of lines of symmetry(12 votes)
- just do it as many times and many ways till you get all you need(18 votes)

- so the amount of sides there is in the shape is how much lines of symmetry there is in that shape(11 votes)
- Symmetry is basically two sides of a shape that are the same. Imagine a triangle split in half. That would be symmetrical. Good luck and keep practicing!(16 votes)

- how do you solve decomposing angles when there is no sign of solving it. it is impossible when you have to subtract the numbers and then the answer is wrong, i never get the decomposing angle questions right, i always get 0% in them. geometry is difficult. isn't it. i always try to solve the questions if they are not right, but it never is right and i never get them right even after having a second go at them.(9 votes)
- Every body can make mistakes just keep trying(15 votes)

- How many line of symmetry does a circle have?(9 votes)
- A circle has infinite amount of lines maybe 20 or more(11 votes)

- whats the meaning of life(12 votes)
- why can we not go back to multiplying(8 votes)
- messi is cool. na bro messi is best(2 votes)

- I think this is pretty easy but at first i didn,t really understand this until i found out what it ment(8 votes)
- Your right!It was hard at first but then i learnd and it was a lot easyer!(4 votes)