Question

Find the equation of a circle which is tangent to x-axis and whose center is at (4,2)

Answer 1

hello : 
an equation x-axis is y= 0
the ridus is the distance betwen the center and x-axis :
r = |(0)(4)+(1)(2)+0 |/√((0)²+(1)²) = 2/1 =2

 an equation of the circle is : (x- 4)²+(y-2)² = 4