Question

The center of a circle is at (0, 0), and the radius of the circle is 3(sqrt)2

. Which equation represents the circle?
A) x2 + y2 = 6
B) x2 + y2 = 18
C) x2 + y2 = 12
D) x2 + y2 = 36

Answer 1

B

Explanation:

The equation of a circle is denoted by:
`(x-h)^2+(y-k)^2=r^2`, where (h, k) is the center and r is the radius.

Here, we see that the center is (0, 0), so h = 0 and k = 0. Also, the radius is
`3√(2)`, so r =
`3√(2)` and
`r^2=(3√(2))^2=9*2=18`.

Then we can write our equation:

`(x-0)^2+(y-0)^2=18`

`x^2+y^2=18`

The answer is B.

Hope this helps!