BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

POint on a circle

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 28
Joined: Sat Jul 05, 2008 11:07 pm
Thanked: 2 times

POint on a circle

by hrishikesh05 » Sat Dec 13, 2008 11:14 pm
A certain circle in the xy-plane has its center at the origin. If P is a point on the circle,
what is the sum of the squares of the coordinates of P?
(1) The radius of the circle is 4.
(2) The sum of the coordinates of P is 0.


I am not satisfied with the explanation.



OA A
Top
Source: — Data Sufficiency |
Senior | Next Rank: 100 Posts
Posts: 59
Joined: Fri Feb 29, 2008 9:00 am
Thanked: 4 times

by agoyal2 » Sat Dec 13, 2008 11:29 pm
The coordinates of any point on the circle, along with the radius will always form a right triangle. So for any point a, b the sum of square of the coordinates will be radius square (Pythagorus theorem)
Top
Master | Next Rank: 500 Posts
Posts: 279
Joined: Wed Sep 24, 2008 8:26 am
Location: Portland, OR
Thanked: 6 times

by pbanavara » Sun Dec 14, 2008 12:42 am
Origin at the center - P is on the circumference : OP is the radius. Use distance formula

sqrt[9x-0)^2 + (y-0)^2] = Radius

Stmnt 1 : Sufficient

Stmnt 2: x+y = 0 x = -y still left with one unknown , insufficient. Hence A

hope this helps

- pradeep
Top
Post new topic Post Reply
• Page 1 of 1