Question

Which of the following circles have their centers on the y-axis?

A.(x - 0)^2 + (y - 0)^2 = 44
B.(x + 1)^2 + (y - 7)^2 = 16
C.(x - 4)^2 + (y - 0)^2 = 22
D.(x - 0)^2 + (y + 5)^2 = 74
?????

Answer 1

the answer is actually (x - 0)^2 + (y + 5)^2 = 74 and (x - 0)^2 + (y - 0)^2 = 44 on apex

Answer 2

Circles A and D have their centers on y-axis.

Explanation:

The standard form of a circle is given by

`(x-h)^2+(y-k)^2=r^2`

Here (h,k) is the center and r is the radius of the circle.

Now, any point which is in the y- axis has x-coordinate equal to zero.

Since, center of the circle is in y-axis. Hence, x coordinate of the circle is zero. Thus, h = 0

`(x-0)^2+(y-k)^2=r^2`

From the given options, circles A and D have their centers on y-axis.