Question

ABCD is a cyclic quadrilateral, find LADB.

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Answer 1

AS ABCD IS A CYCLIC QUADRILATERAL

ANGLE DCB+ANGLE DAB =180°

SO

120°+ ANGLE DAB=180°

ANGLE DAB = 180°-120°=60°

NOW AS WE KNOW THAT

THE SUM OF ALL ANGLES OF A TRIANGLE IS EQUAL TO 180°

SO

IN ∆ADB

ANGLE ADB+ANGLE DAB+ANGLE DBA=180°

GIVEN ANGLE DBA =50°

AND WE HAVE FOUND

ANGLE DAB =60°

SO

ANGLE ADB+60°+50°=180°

ANGLE ADB=70°