Mathematics - Properties of Triangle Question with Solution | TestHub

Put r=$\Delta$/s and $r_a$=$\Delta$/(s-a), etc. The given equality rearranges to ${\tan }^2\left(B/2\right)$=(a-c)/b. Since 60°<B<90°, 1/3<${\tan }^2\left(B/2\right)$<1, so b<3(a-c)<3b. Hence D.