It is known that: as shown in the figure, ∠ B = ∠ C = 90 °, M is the midpoint of BC, DM bisects ∠ ADC. (1) prove that am bisects ∠ bad; (2) try to explain the position relationship between DM and am? (3) What is the relationship between CD, AB and ad? Write the results directly

(1) It is proved that me ⊥ ad is equal to e, ⊥ MC ⊥ DC, me ⊥ Da, MD, ⊥ ADC, ≁ me = MC, ≁ m is the midpoint of BC, ≁ MB = MC, ≁ me = MC, ≁ me = MB, and ≁ me ⊥ ad, MB ⊥ AB, ≁ am, ≁ DAB

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1. As shown in the figure, ∠ B = ∠ C = 90 °, point m is the midpoint of BC, am bisects ∠ DAB
2. As shown in the figure, in the quadrilateral ABCD, ab = ad, CB = CD, point P is the point on AC, PE ⊥ BC is in E, PF ⊥ CD is in F, proving: PE = PF
3. In ABCD, ab = AC, CB = CD, point P is a point on diagonal AC, PE is perpendicular to BC and E, PF is perpendicular to CD and F, PE = PF is proved
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