Question

How do you find the a, b, c for `(x + 3)^2/9 + (y – 9)^2/25 =1`?

Answer 1

`a=5`
`b=3`
`c = 4`

Explanation:

This is the equation for an ellipse - the standard form for an ellipse is`(x-h)^2/b^2 +(y-k)^2/a^2 = 1`.

Note also that `b^2+c^2 = a^2`.

See Ellipses for a more detailed description.

So the centre of the ellipse is `(-3,9)`
`a=5`
`b=3`
`c=sqrt(25-9) = 4`