6. In the diagram, O is the centre of the two concentric circles and ABCD is a straight line. BC= 30 cm, and the radii of the two circles are 25 cm and 29 cm, respectively.
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6 In the diagram O is the centre of the two concentric circles and ABCD is a straight line BC 30 cm and the radii of the two circles are 25 cm and 29 cm respect class=