如图,在△ABC中,CE平分∠ACB,CF平分∠ACD,且EF∥BC交AC于M,若CM=3.5,则CE2+CF2的值为________.

如图,已知AB∥CD,E是AB上一点,DE平分∠BEC交CD于D,∠C=80°,则∠D的度数是()


A.40° | B.45° | C.50° | D.55° |
如图,已知四边形ABCD中,∠C=∠D=90°,AE平分∠DAB,BE平分∠ABC,且E在D上.
(1)求∠AEB;
(2)求证:DE=CE.

(1)求∠AEB;
(2)求证:DE=CE.
