AE bisection BAC.CE Divide ∠ ACD equally (1) if AB / / CD, judge whether △ ace is a right triangle, please explain the reason; (2) if ace is a right triangle AE bisection BAC.CE Bisecting ∠ ACD (1) If AB / / CD, judge whether △ ace is a right triangle, please explain the reason; (2) If the triangle ace is a right triangle, judge whether the line AB is parallel to the line CD, please explain the reason

AE bisection BAC.CE Divide ∠ ACD equally (1) if AB / / CD, judge whether △ ace is a right triangle, please explain the reason; (2) if ace is a right triangle AE bisection BAC.CE Bisecting ∠ ACD (1) If AB / / CD, judge whether △ ace is a right triangle, please explain the reason; (2) If the triangle ace is a right triangle, judge whether the line AB is parallel to the line CD, please explain the reason

(1) AE bisection ﹥ BAC, ﹥ EAC = 1 / 2 ﹥ BAC; CE bisection ﹥ ACD, ﹥ ECA = 1 / 2 ﹥ ACD; AB / / CD, complementary internal angles, ﹥ BAC + ﹥ ACD = 180 °, EAC + ﹥ ECA = 1 / 2 * 180 ° = 90 °, AEC = 180 ° - (﹥ EAC + ﹥ ECA) = 90 ° so △ ace is a right triangle. (2), not necessarily