Question

Two concentric circles are of radii $5cm$ and $3cm$. Find the length of the chord of the larger circle which touches the smaller circle.

Answer 1

REF.Image

In $△OBP$, by Pythagoras theorem

$O{B}^2=O{P}^2+B{P}^2$

$\Rightarrow 5^2=3^2+B{P}^2\Rightarrow BP=4cm$

Similarly AP = 4 cm $\Rightarrow$ AB= 8 cm