Question

Two concentric circles are of radii $6.5cm$ and $5.2cm$. Find the length of the chord of the larger circle which touches the smaller circle

Answer 1

${AP}^2={AO}^2-{OP}^2$

$\Rightarrow {AP}^2={6.5}^2-{5.2}^2=42.25-27.04=15.21$

$\Rightarrow AP=\sqrt{15.21}=3.9$m

$AB=2\times 3.9=7.8$cm