In the xy-plane, the point (-2, -1) is the center of a circle. The point (1, -1) lies inside the circle and the point (-2, 4) lies outside the circle. If the radius r of the circle is an integer, then r = Select:
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 (1, -1) is 3 units   (both points are on y=-1 line so the distance will simply be  1-(-2)= 
<gadget id="calculator"> 1-(-2)</gadget>
<output>3</output>
3)   So the radius must be more than 3 units.   The distance between the center (-2,-1) and the point outside the circle (-2,4) is 5 units   (both points are on x=-2 line so the distance will simply be  4-(-1)= 
<gadget id="calculator"> 4-(-1)</gadget>
<output>5</output>
5)   So the radius must be less than 5 units, which implies 3 &lt; r &lt; 5, thus as r is an integer then r=4.   Answer: 4.
<result>C</result>
In the xy-plane, the point (-2, -1) is the center of a circle. The point (1, -1) lies inside the circle and the point (-2, 4) lies outside the circle. If the radius r of the circle is an integer, then r =