Inner Common Tangent of Two Circles

①This example demonstrates how to construct the inner common tangent lines of two circles, i.e., lines that are tangent to both circles and lie between them. ②Core mathematical concepts include tangent properties of circles, definition of inner common tangents, perpendicularity of radius to tangent at the point of tangency, and the use of auxiliary points such as midpoints and intersections. ③Construction details: from the summary, the commands used are Circle, Segment, Midpoint, Intersect, Line, and Angle; objects include A, B, c, C, D, d, f, g, h, e, E, k, F, i, j, G, l, m, H, n, p, q, α, β, reflecting a complete compass-and-straightedge construction process. ④Suitable for high school plane geometry or analytic geometry courses, to understand tangent properties and geometric construction methods, and as a GeoGebra construction teaching example.