In the quadrilateral ABCD, BD is perpendicular to ad, AC is perpendicular to BC, e is the key point of AB, and the verification angle EDC = angle ECD Wait online. It's urgent
prove:
Because triangle abd and triangle ABC are right triangles, and E is the midpoint of hypotenuse ab
So from the middle line on the hypotenuse of a right triangle equal to half of the hypotenuse, we can get: de = CE = AB / 2
So angle EDC = angle ECD
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