What is the locus of a point P which moves on one side of a straight line XY, so that the angle XPY is always equal to 90

^{o}?-
**A.**

the perpendicular bisector of XY -
**B.**

a right-angled triangle -
**C.**

a circle -
**D.**

a semi circle

##### Correct Answer: Option D

##### Explanation

Since XY is a fixed line and

XPY = 90^{o} P is on one side of XY

P_{1}P_{2}P_{3}……P^{n} are all possible cases where

XPY = 90^{o} the only possible tendency is a semicircle because angles in semicircle equals 90^{o}