Question

In $△$ ABC, if a = 16, b = 24 and c = 20, then cos $\frac{B}{2}$ =
[MP PET 1988]

• A. 3/4
• B. 1/4
• C. 1/2
• D. 1/3

Answer 1

The correct option is A 3/4

2s = a + b + c : cos $\frac{B}{2}=\sqrt{\frac{30\times 6}{320}}=\frac{3}{4}.$