垂径定理:垂直于弦的直径平分这条弦,并且平分弦所对的两条弧。 这个定理是圆这一章比较重要的定理,讲的是垂直于弦的直径的性质。同学们必须熟练地掌握,并要学会运用垂径定理及其推论解决有关的证明、计算和作图问题。 Trailing theorem: Divide the string perpendicular to the diameter of the string and divide the two arcs that the string meets. This theorem is a more important theorem of the chapter on circles, which is about the properties perpendicular to the diameter of the string. Students must be skilled in mastering, and must learn to use the vertical theorem and its inference to solve the relevant proofs, calculations and mapping problems.