Question

Which of the following points lies on the circle whose center is at the origin and whose radius is 5? A (-3, 4) B (1, -2) C (, )

Answer 1

Do you have any idea on how this is solved? When (h, k) both equal 0; you get a special formula. x^2 + y^2 = r^2 --- x^2 + y^2 = 25 

And you can kinda look at the graph and guess which one it'll be. 

Take a look at the graph here: http://prntscr.com/bj7ixd

Answer 2

Answer with explanation:

Equation of Circle having Center, (a,b) and , radius =r units , is written as

 →→(x-a)²+(y-b)²=r²

Equation of circle ,having center at the Origin and radius =5 units will be equal to:

  →→ (x-0)²+(y-0)²=5²

⇒x² + y²=25

If, you substitute, x=-3. and , y=4 ,in the above equation

L HS= (-3)² +4²

     = 9 + 16

     = 25

=R HS

So, Point , (-3,4) lies on the circle.

Option A: (-3,4)