The question reads thus
Find the equation of a circle that touches the x axis at the origin and also touch the line 12x+5y=60

Now,...if i consider the centre of the circle is (a,b)
==>the radius r=|b|
That's all i could deduce
I also thought equating the equations of the cricle and the line would be a good idea to get the point of intersection...but i don't see how it could help m

Could someone help me solve the question and explain the resaoning behind so that i can know what to do next time

In addition...in case we need to find the chord of intersection of two circles are we just supposed to equate them?
Thanks in advanced
Lee