Question

In two concentric circle, a cord of larger circle touches smaller circle. If the chord is $8cm$ and the diameter of the smaller circler is $6cm$, then find the diameter of the larger circle.

Answer 1

$ACO={90}^0$

$\left({AO}^2\right)=\left({OC}^2\right)+\left({AC}^2\right)$

$\left({AO}^2\right)=\left(3^2\right)+\left(4^2\right)$

$\left({AO}^2\right)=9+16$

$\left({AO}^2\right)=25$

$\left({AO}^{}\right)=5$

$AO=5=cm$

$d=AO\times 2$

$5\times 2$

$10cm$