The equation of a circle which touches the x -axis and whose centre is 1 , 2 is

The equation of a circle which touches the x-axis and whose centre is 1,2 is
  1. (x-2)2+(y-1)2=4
  2. (x-1)2+(y-2)2=4
  3. (x-1)2+(y+2)2=4
  4. (x+2)2+(y-1)2=4

Solution

If centre is (1,2) and circle is touching x-axis, then radius is y-coordinate of centre.

⇒r=2

⇒(x-1)2+(y-2)2=22

Asked in: AP EAMCET 2020 (23 Sep Shift 1)

Practice more Circle questions on Aicharya