Question

please help me fast..
its really important.
please answer with explanation .


*please dont answer if you dont know.. just dont waste my time :( *​

Answer 1

OA = OB ... {radius }

•°• triangle is isosceles

•°• ∠OAB = ∠OBA = 40° ...{isosceles angle}

∠OAB + ∠OBA + ∠AOB = 180° .. {sum of all angles }

40 + 40 + ∠AOB = 180

∠AOB = 180 - 80

∠AOB = 100°

∠AOB = m(arcAB) = 100° ...Central angle

•°• ∠ACB = 1/2 m(arcAB) ...{inscribed angle theorem}

∠ACB = 1/2 × 100 = 50°

∠ACB = 50°

may be option are incorrect, but my answer is 99% correct