We have just a dry compass, unable to draw
It just allows to get the intersection point of a circle with a straight line.
The dry compass is traditionnaly used to transport distances,
and doesn't usually allow this construction. Here we do. It is a 'marginal' usage of the dry compass.
With an (unmarked) straightedge and this dry compass, construct :
- A square with given side AB
- Midpoint of a given segment AB
- An equilateral triangle with given side AB
- Two circles are defined by their given centers and radii.
We are unable to draw them, but construct their intersect points ?