《三角形的内角》说课稿11.20

1,2180o31210180,1180o23?1.ABCA=80B=C,C=2.ABC,BAC=40B=75,ADABC.ADB3CA50,BA80CB40BA,CABC?CA,BACB.1.:11.237.2AMN+MNF+NFC=360ABCD,;11.2.1180.