Question

Find the equation of the circle with center at (0, 0) and diameter of 18.

Answer 1

`{x}^(2) + {y}^(2) = 81`

Explanation:

The general for for the equation of a circle is

`{(x - a)}^(2) + {(y - b)}^(2) = {r}^(2)`

Where a is the x coordinate of the centre, b is the y coordinate of the centre and r is the radius.

In your case, a=0, b=0, r=9

Substituting these values into the general form gives the answer.