So you can try to do this way :
- let A and B be two points of the plane
- get the length AB with your compass
- draw the circle of center A, and length AB. This will make all the points that are at equal distance to A than B.
- draw the same circle, but of center B. This will make all the points that are at equal distance to B than A.
There will be two intersections. See what the properties of the sides of the formed triangle are