Find the equation of the circle with its centre at (3, 2) and which touches to the line x+2y-4=0.

Explanation

`abs(bar(PC))=abs((ax_1+by_1+c)/sqrt(a^2+b^2))`
= `(1 xx 3 + 2 xx 2 - 4)/sqrt(1^2+2^2) = 3/sqrt5` = radius
`therefore` Equation of the circle is
`(x-h)^2+(y-k)^2=a^2`
or, `(x-3)^2+(y-2)^2=9/5`