Question

How do you write an equation of a circle with center (0,0) and radius is 169?

Answer 1

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

This circle is therefore `(x-0)^2+(y-0)^2 = 169^2`

`x^2+y^2=28561`

Comment: Given that `169` is `13^2` I suspect this question should read 'the square of the radius is 169'