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AB and CD are two parallel chords of a circle with centre O such that AB = 6 cm and CD = 12 cm. The chords are on the same side of the centre and the distance between them in 3 cm. The radius of the circle isA. 6 cm B. 5\(\sqrt2\) cm C. 7 cm D. 3\(\sqrt5\) cm |
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Answer» Option : (D) Given that, AB || CD (Chords on same side of centre) AO = CO (Radii) OL and OM perpendicular bisector of CD and AB respectively CL = LD = 6 cm AM = MB = 3 cm LM = 3 cm (Given) In COL, CO2 = OL2 + 62 ...(i) In AOM, AO2 = AM2 + OM2 = 32 + (OL + LM)2 = 9 + OL2 + 9 + 6O L OL2 = AO2 - 18 - 6O L ... (ii) Using (ii) in (i), OL = 3 cm Putting OL in (i), AO2 = \(\sqrt{45}\) AO = 3\(\sqrt{5}\) |
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