Question

Circle P is tangent to the x-axis and the y-axis. If the coordinates of the center are (r, r), find the coordinates of the points of tangency. (0, r) and (r, 0) (r, r) and (0, 0) (0, ½r) and (½r, 0)

Answer 1

The y-axis has equation x=0. The point of tangency on the y-axis is on the line y=(something) through the center point of the circle, (r, r). Consequently, the (something) must match the y-coordinate of the circle center, r. That is, the point of tangency is the point of intersection of x=0 and y=r: (0, r).

The first selection is correct:
  (0, r) and (r, 0)

Answer 2

Answer:

The y-axis has equation x=0. The point of tangency on the y-axis is on the line y=(something) through the center point of the circle, (r, r). Consequently, the (something) must match the y-coordinate of the circle center, r. That is, the point of tangency is the point of intersection of x=0 and y=r: (0, r).

The first selection is correct:

 (0, r) and (r, 0)