Question

Draw a perpendicular bisector with ruler and compass

Answer 1

But of what length,perpendicular bisector you are saying

Answer 2

let the line AB which you want to bisects perpendicularly

Taking A as centre draw an arc wuth compass of radius more than half of AB on the both side of line segment

taking B as centre with same radius intersect previous arc on both side

Let the intersection point of both arc are G AND H

JoiB GH which intersect AB at any point N

GN is perpendicular bisector of AB