In a circle of diameter 20cm, chords AB and CD are parallel to each other. BC is diameter. If AB is 6 cm from the centre of the circle, what is the length (in cm) of the chord CD ?
Answer & explanation
Correct answer: option 4
We know that,
H2 = B2 + P2
Diameter of the circle = 20 cm
PO = 6cm
AB = CD
OP ⊥ AB
Radius (OB) = \(\frac{20}{7}\) = 10 cm
So, PB = \(\sqrt {10^2 – 6^2}\) = 8cm
So, AB = (PB + PA) = 8 + 8 = 16 cm
CD = AB = 16 cm