A and B are two fixed points. What will be the locus of the point P such that ∠ APB=90∘
The locus of point P is the circumference of a circle with AB as the diameter.
Join AB and draw a circle with AB as diameter. The locus of point P is the circumference of this circle, since the angle in a semi circle is 90∘.
Therefore, whatever be the position of point P, the measure of ∠ APB will always be 90∘.