Question

the question is in the pic

Answer 1

if we draw OA and OB. then AOB triangle is form
OA =OB =13c.m
AB =24c.m
then
$om = \sqrt{ {13}^{2} } - \sqrt{ {24}^{2} } \div 4$
$om = \sqrt{169} - \sqrt{576} \div \sqrt{4}$
$om = \sqrt{169} - \sqrt{144}$
$om = 5c.m$