Question

n. In a AABC, AB = AC. A circle passing through
B and C intersects the side AB and AC at D
and E respectively. Prove that: DE = BC
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Answer 1

Answer:

Step-by-step explanation:

To prove: DE || BC.Proof:In order to prove that DE || BC it is sufficient to show that ∠B = ∠ADEIn ΔABC,AB = ACIn the cyclic quadrilateral CBDE, side BD is produced to A.It is the property of cyclic quadrilateral that its exterior angle is equal to the opposite interior angle.⇒ ∠ADE = ∠C .... (2)From (1) and (2), we get, which forms corresponding angles.Hence DE || BC.