You are only given the three midpoints of the sides of a triangle. How can you construct the original triangle?
Prove that, given any three parallel lines, an equilateral triangle
always exists with one vertex on each of the three lines.
Medieval stonemasons used a method to construct octagons using ruler and compasses... Is the octagon regular? Proof please.
Keeping the radius fixed, move the point of the compasses to the
circumference and mark off one radius length around the
Move the point of the compasses on to that mark and repeat until
you have six marks equally spaced around the circle.