Question

In the figure AB is the diameter and CD is parallel to the diameter. AB = 8cm,BD = 2cm, find CD

Answer 1

If we draw a perpendicular DP to AB from D. Then PA x PB = PD². 

Here PB = x, then PA = 8 – x.

x(8 – x) = PD² , 2² = x² + PD² 

x(8 – x) = 4 – x² , 8x – x² = 4 – x² 

8x = 4, x = \(\frac{1}{2}\)

Similarly, let us draw a perpendicular CQ to AB from C

AQ = ,PQ = 8 – \((\frac{1}{2}+\frac{1}{2})=7\)

CD = 7cm