Question

A chord is $12cm$ away from the centre of the circle of radius $15cm$. Find the length of the chord.

Answer 1

Radius of a circle $\left(OA\right)=15cm$
Distance from centre to the chord $\left(OC\right)=12cm$
In the right $△OAC$,
${AC}^2={OA}^2-{OC}^2$
$={15}^2-{12}^2$
$=225-144$
$=81$
$AC=\sqrt{81}$
$=9$
Length of the chord $\left(AB\right)$
$=AC+CB$
$=9+9$
$=18cm.$