Question

what is the value of OD ​

Answer 1

$draw \: nm \: perpndicular \: to \: od \\ so \: nm = 15cm \\ and \: md = 9cm \: \: \: om= r - 9 \\ {on}^{2} = {nm}^{2} + {om}^{2} \\ {r}^{2} = {15}^{2} + ({r - 9})^{2} \\ 0 = 225 + 81 - 18r \\ r = \frac{306}{18} = 17cm$