Question

What is the equation for a circle with a center of 4,7 and a radius of 7 ?

Answer 1

`x^2 + y^2 - 8x - 14y + 16 = 0`

Explanation:

Where

• `r =` Radius of circle
• `(h,k) =` coordinates of centre of circle

`(x - 4)^2 + (y - 7)^2 = 7^2`

`[x^2 + 4^2 - (2 × x × 4)] + [y^2 + 7^2 - (2 × y × 7)] = 7^2`

`x^2 + 16 - 8x + y^2 + cancel(49) - 14y = cancel(49)`

`x^2 + y^2 - 8x - 14y + 16 = 0`