we are going to construct a line perpendicular to a given line L passing through a given point on L there are two ways to carry out this construction and both of these need to be known in the first one we are going to use a compass and a straight edge in this example we're going to construct a perpendicular line passing through a the first thing we're going to do is we're going to place our compass on a and draw an arc on either side we now need to make sure that the compass width is more than the width from The Arc to the point a we then place our compass on our new arc and draw an arc above the line and without changing the width we do the same on the other side we're going to mark this point of intersection and using a straight edge we are going to join this to our point a and here we can see we have our perpendicular line passing through a we are now going to look at the second method in the second method we use set Square we place our set Square on on our line at the point a and we draw a line from this on the right angle and here we can see we have a perpendicular line passing through a now try both of these methods out for yourself and we'll see you in the next lesson [Music]