Question

What is the value of b?

Answer 1

Answer:

17

Step-by-step explanation:

Using the law of cosines in ΔABC

b² = a² + c² - (2ac cosB) ← substitute in values

   = 25² + 28² - (2 × 25 × 28 × cos36.9°)

   = 625 + 784 - 1400 cos36.9°

   = 1409 - 1400 cos36.9° ( Take the square root of both sides )

b = $\sqrt{1409-1400cos36.9}$ ≈ 17 ( nearest whole number )