成题,不是陈题,成题是久经考验之历久长新的好题.关于一付三角板的拼接问题……用一组题来复习立体几何的主要定理和解题方法,用一组题来强化对立几的综合复习,确实能达到事半功倍的效果.题组△ABC和△ABC是一付三角板,△ABC为等腰直角三角形,∠A=90°,△BCD中,∠C=90°,∠D=60°,公共边BC=a,若两块三角板以BC为 Into a problem, not a title, into a title is a proven long-lasting new good question on a pair of triangular panels stitching problem ... ... with a group of questions to review the three-dimensional geometry of the main theorem and problem solving methods, with a group of questions To strengthen the comprehensive review of a few more, can really achieve a multiplier effect. The group △ ABC and △ ABC is a pair of triangular plate, △ ABC isosceles right triangle, ∠A = 90 °, △ BCD, ∠C = 90 ° , ∠D = 60 °, common side BC = a, if the two triangle to BC