Line Symmetry

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Lesson Objective
In this lesson, we will learn about line symmetry and what is line of symmetry.
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About This Lesson
Looking at the picture on the right, we can see that the two sides of the picture are identical. Knowing this, we can say that this picture is symmetrical.

Now, we will learn about line symmetry and what is line of symmetry.

You can proceed by reading the study tips first or watch the math video or try out the practice questions.
line symmetry for a fractal picture

Study Tips

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Tip #1
When we draw line across this equilateral triangle as shown in the picture, we can see that both sides of the triangle are the identical.

With this, this triangle is symmetrical along this line and this line is called line of symmetry.

The math video below will show you more on this visually.
line of symmetry of a triangle
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Tip #2
Next, when we observe carefully, this equilateral triangle in fact has 3 lines of symmetry.

So next time, when you are given a shape to find all the lines of symmetry, be reminded to carefully analyze the shape carefully to avoid missing out any of these lines.

no rotational symmetry
Now, watch the following math video to learn more.

Math Video

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Click play to watch video

If the above player doesn't work, try this direct link.

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Math Video Transcript

Practice Questions & More

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Multiple Choice Questions (MCQ)
Now, let's try some MCQ questions to understand this lesson better.

You can start by going through the series of questions on line symmetry or pick your choice of question below.
  1. Question 1 on finding the lines of symmetry of a five-pointed star
  2. Question 2 on line symmetry of a parallelogram