Question

Write the standard equation of a circle having center (9, 1) and a point on circle at (-2, -5).

Answer 1

`(x-9)^2+(y-1)^2=(√(157) )^2.`

Explanation:

1. the rule is:

(x-x₀)²+(y-y₀)²=r², where (x₀;y₀) - the centre of the given circle, r - its radius.

2. using the given point (9;1) and the centre (-2;-5) it is possible to calculate 'r²':

`r^2=(9+2)^2+(1+5)^2=157=√(157^2) .`

3. finally,

`(x-9)^2+(y-1)^2=√(157^2) .`