两圆的位置关系有外离、外切、相交、内切、内含五种关系,当相切的两个圆,除了切点外,每个圆上的点都各在另一个圆的外部时,我们称这两个圆外切.与外切两圆的有关的计算问题,常构造直角梯形及直角三角形,用解直角三角形的知识和几何知识综合去解构造后的直角三角形.下面举例说明. The positional relationship of the two circles is outer, outer, intersecting, inner and inner. The two circles are tangent. In addition to the cut points, the points on each circle are each outside the other circle. At the time, we called these two circles circumscribed. For the computational problems related to circumscribing two circles, we often construct right-angled trapezoids and right-angled triangles. We use the knowledge of knowledge of right-angled triangles and geometric knowledge to synthesize the constructed right-angled triangles. Instructions.