Perpendicular Bisectors - Three Essential Constructions

Perpendicular bisectors are lines that cut through another line at exactly 90 degrees, splitting it into two equal parts. You'll need to master three different types of constructions that pop up regularly in your maths exams.

The basic perpendicular bisector of a line segment is your starting point. Place your compass on one end of the line and set it to just over halfway. Draw arcs above and below the line, then repeat from the other end using the same compass width. Connect where the arcs cross - that's your perpendicular bisector!

For a perpendicular from a point to a line, you're creating a right angle from an external point. Put your compass on the given point and mark two spots on the line at equal distances. Then construct the perpendicular bisector of these two new points, making sure it passes through your original point.

The perpendicular from a point on a line is slightly different. Start with your compass on the point that's already on the line, then mark equal distances on both sides. Find the perpendicular bisector of these two new points, and you're sorted!

Quick Tip: Keep your compass width consistent throughout each construction - changing it halfway through will mess up your accuracy!