我们知道,圆是由圆心和半径确定的,其中圆心确定圆的位置,半径确定圆的大小.因此,只要确定了圆心的位置和半径的大小,那么圆也就确定了.这里归纳一下确定圆心和半径的几个常用方法.1.用圆心和圆上的某一点确定圆这实际上就是告知了圆心和半径,显然,圆心到该点的距离就是圆的半径. We know that the circle is determined by the center of the circle and the radius. The center of the circle determines the position of the circle. The radius determines the size of the circle. Therefore, as long as the position and radius of the center of the circle are determined, the circle is determined. Several common methods for radius and radius are: 1. Determine the circle with a circle and a certain point on the circle This actually informs the center and the radius. Obviously, the distance from the center to the point is the radius of the circle.