Question

I need help understanding how to do this .

Answer 1

To draw the equation of a circle, you need the center coordinates $(h,k)$ and the radius $r$.

Once you know them, you can write the equation for the circle as

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

We can eyeball the center coordinates: from the origin, we have to go one step right and two steps below, so the coordinates are $(1,-2)$

For the radius, you can see that if you move three units up, down, left or right from the center, you reach the circumference. So, the radius is 3.

Given everything we said above, we're ready to write the equation:

$(x-1)^2+(y+2)^2 = 9$