Question

heyyyy solution plzzz​

Answer 1

let ABCD be the cyclic trapezium with AB IICD.

through C draw CE parallel to AD

AECD is a parallelogram.

angle D=angle AEC.... opp angles of a parallelogram are equal....(i)

angle D+angle ABC=180... opp angles of a cyclic quadr are supplementary....(ii)

from (i) and (ii)

angle AEC+angle ABC=180

angle AEC+angle CEB= 180...linear pair

angle ABC= angle CEB ..(iii)

CE=CB... sides opp equal angles are equal.(iv)

CE=AD...opp sides of parallelogram AECD.

from (iv) we get

AD=CB

Thus cyclic quadrilateral ABCD is isoceles.