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.) (√5,√5 )

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.) (√5,√5 )

anonymous · Answer

the equation of a circle centered at the origin with radius of r is
$$x^2+y^2=r^2$$
This circle's equation is 
$$x^2+y^2=5$$
Which of the points makes that equation true?

anonymous · Answer

you actually have to plug the numbers in to find the answer

anonymous · Answer

i think i am doing it wrong

anonymous · Answer

what did you get for x² + y² when you put in (-3, 4)?

anonymous · Answer

|dw:1435248007654:dw|

anonymous · Answer

25

anonymous · Answer

ok. that's not 5, so (-3,4) isn't the answer.
Try (1, -2)

anonymous · Answer

5

anonymous · Answer

right. so (1, -2) is the answer since it gives 5 on the left to match the 5 on the right