下面就是
GRE数学真题和解析(20)
25.In the xy-plane, the point with coordinates (–6, –7) is the center of circle C.
The point with coordinates (–6, 5) lies inside C, and the point with coordinates (8, –7) lies outside C. If m is the radius of C and m is an integer, what is the value of m ?
m =_____
这个题大家可以画个坐标图，标出那几个点，(-6,5)在圆内，那么半径m>5-(-7)=12(之所以能这么算，是因为圆心坐标跟这个点的横坐标相同),而点(8，-7)在圆外，那么m<8-(-6)=14,又因为m是整数，因而m=13了
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