In figure, if OA = 5 cm, AB = 8 cm and OD is perpendicular to AB, then CD is equal to -Maths 9th

1 Answer

Answer :

(a) We know that, the perpendicular from the centre of a circle to a chord bisects the chord. AC = CB = 1/2 AB = 1/2 x 8 = 4 cm given OA = 5 cm AO2 = AC2 + OC2    (5)2 = (4)2 + OC2 25 = 16 + OC2 OC2 = 25-16 = 9 OC = 3 cm [taking positive square root, because length is always positive] OA = OD [same radius of a circle] OD = 5 cm CD = OD – OC = 5 – 3 = 2 cm

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