Draw a circle with centre at point O. Draw its two chords AB and CD such that AB is not parallel to CD. Draw the perpendicular bisectors of AB and CD. At what point do they intersect?
Steps of construction:
With center O and any radius, draw a circle
Draw two chords AB and CD.
With center A and radius more than 1/2 AB draw arcs, one on each side of AB
With center B and same radius draw arcs cutting previous arcs at P and Q respectively.
Join PQ
With center D and radius more than 1/2 DC draw arcs, one on each side of DC
With center C and same radius, draw arcs cutting previous arcs at R and * respectively
Join RS
Both perpendicular bisector PQ and RS intersect each other at the center O of he circle.