Question

What is the equation of the circle with center (0,1) and a radius of 10?

a. x^2 + (y-1)^2 = 100

b. (x-1)^2 + y^2 = 100

c. x^2 + (y+1)^2 =100

Answer 1

The equation of a circle:

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

(h, k) - a coordinates of the center

r - a radius

We have:

`(0,\ 1)\to h=0;\ k=1\\r=10`

substitute:

`(x-0)^2+(y-1)^2=10^2\\\\x^2+(y-1)^2=100`

Answer: a. x^2 + (y-1)^2 = 100