In the figure, points P and Q lie on the circle with center O. What is the value of S? (A) 1/2 (B) 1 (C) root(2) (D) root(3) (E) root(2)/2

This one is very tough, but tests whether you realize that: 1) OP = OQ. and 2) If you drew a line straight down from P to the x-axis, you would form a triangle of base 1 and height root(3), so it will be a 30-60-90 triangle. The angle measures are key because from them you can deduce a lot about s and t. it's tough to explain without drawings but the answer is B. Have a look at a detailed solution, including a video solution: this is GMATprep question 1082. Set topic='Geometry, Coordinate' and difficulty='700+' in the drill generator to practice similar questions. -Patrick

The attached figure shows why s = 1. Anytime you see Root3, you should think: 30-60-90 triangle. Hope this helps!

After every 90 degrees the co-ordinates will get inverted with the sign assigned according to the quadrant in which the point lies. The co-ordinates is (-V3,1).After 90 degree it will become (1,V3)[Note it is in first quadrant,so both x and y are positive]

Patrick_GMATFix wrote:Have a look at a detailed solution, including a video solution: this is GMATprep question 1082. Set topic='Geometry, Coordinate' and difficulty='700+' in the drill generator to practice similar questions. -PatrickVideo solution is very helpful! Thank you guys for your help