# Lesson video

In progress...

Hello, my name is Mr. Clasper and today we are going to be constructing perpendicular bisectors.

What is a perpendicular bisector? A perpendicular bisector is a line which cuts another line exactly in half.

The lines meet at right angles.

So, if I have a straight line, represented by this red line, the perpendicular bisector would intersect the red line at right angles and at the midpoint of the red line.

Here are some questions for you to try.

Pause the video to complete your task and click resume once you're finished.

So to bisect a line means to cut a line exactly in half.

When two lines meet at a right angle, they are called perpendicular lines.

And a perpendicular bisector cuts a line in half at right angles.

We're going to construct a perpendicular bisector.

To do this, we need a compass and you need to make sure you set the compass so that it is slightly more than half of the given line you are trying to bisect.

Once I've done this, I'm going to draw a curve.

I'm then going to move my compass point to the opposite side of my line, keeping the compass at the same distance, and I'm going to draw another curve.

My line bisector is a line segment, which would join the two intersections of the curves I've drawn.

This is my perpendicular bisector.

Here are some questions for you to try.

Pause the video to complete your task and click resume once you're finished.

So to check your work, just ensure that you have started with a 10 centimetre line and you need to make sure that your bisector meets at a right angle.

And for the first parts of a question two, it needs to be five centimetres in.

And for question three, likewise for this one, make sure you have an 8.

2 centimetre long line and to check it is in the middle, it should be 4.

1 centimetres from either end.

And that is the end of our lesson on constructing perpendicular bisectors.

Why not have a go at the exit quiz to show off your skills.

I'll hopefully see you soon.