Originally Posted by

**mluo** Consider a fixed line segment AB=4. Also consider a line segment CD, such that

AB=CD=4, and that AB is the perpendicular bisector of CD AND CD is the perpendicular bisector of AB.

Now, consider the set of all points P on CD (which there are inifineitely many). For every unique point P, there are two unique points Q such that QBPA is cyclic (all four points lie on a circle) and that QP is bisected by AB.

The set of all possible points Q creates a familiar figure.

What is that figure and what is the area of that figure?

Prove this.

I said it was a cirlce with area 4pi, but he said it was wrong?

What other familar shape can it possibly be? If i draw it it seems like a circle (i just plotted a lot of points)