In the xy-plane, the point (2, 1) is the center of a circle. The point (-2, 1) lies inside the circle and the point (2, -5) lies outside the circle. If the radius r of the circle is an integer, then r =
Choose the correct choice from the following answers.
A) 6
B) 5
C) 4
D) 3
E) 2
An easy way to solve this question will be just to mark the points on the coordinate plane.   You'll see that the distance between the center (2, 1) and the point inside the circle (-2, 1) is 4 units   (both points are on y=1 line so the distance will simply be  2-(-2)= 
<gadget id="calculator"> 2-(-2)</gadget>
<output>4</output>
4)   So the radius must be more than 4 units.   The distance between the center (2,1) and the point outside the circle (2,-5) is 6 units   (both points are on x=2 line so the distance will simply be  1-(-5)= 
<gadget id="calculator"> 1-(-5)</gadget>
<output>6</output>
6)   So the radius must be less than 6 units, which implies 4 &lt; r &lt; 6, thus as r is an integer then r=5.   Answer: 5.
<result>B</result>
In the xy-plane, the point (2, 1) is the center of a circle. The point (-2, 1) lies inside the circle and the point (2, -5) lies outside the circle. If the radius r of the circle is an integer, then r =