point on a circle

[neoreaves]

IN THE XY-PLANE, POINT (R,S) LIES ON THE CIRCLE WITH CENTER AT ORIGIN. WHAT IS THE VALUE OF R^2 + S^2?

I. THE CIRCLE HAS RADIUS 2
II. THE POINT (a, -a) LIES ON THE CIRCLE

[liferocks]

IN THE XY-PLANE, POINT (R,S) LIES ON THE CIRCLE WITH CENTER AT ORIGIN. WHAT IS THE VALUE OF R^2 + S^2?

I. THE CIRCLE HAS RADIUS 2
II. THE POINT (V2, -V2) LIES ON THE CIRCLE

IMO ans is D

since the center of the circle is origin the distance of point (R,S) from center will be sqroot(R^2+S^2) and (R,S) lies of the circle so this brings down the question to the fact that what is the radius of the circle as that is equal to sqroot(R^2+S^2) or
R^2+S^2=square of radius

now statement 1 provides the radius directly-->Suff
Statement 2 provides another point on circle.so square of radius will be radius will be 2+2=4-->suff

hence either of the statements is sufficient to ans

[neoreaves]

ok i see what you are saying let me edit the question ....instead of sqrt2 lets put in a

[liferocks]

ok i see what you are saying let me edit the question ....instead of sqrt2 lets put in a

hmm..in this case option 2 gives that the radius is (V2)a.we do not know what is a hence this should be insuff.
then only 1 is suff .So ans will be A
is the approach correct?

[eaakbari]

IMO A

[deepesh.gupta]

I am confused between A and D. Can we have experts views?

ok i see what you are saying let me edit the question ....instead of sqrt2 lets put in a

hmm..in this case option 2 gives that the radius is (V2)a.we do not know what is a hence this should be insuff.
then only 1 is suff .So ans will be A
is the approach correct?