Question

What is the value of b?

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Round only your final answer to the nearest whole number.

Answer 1

17

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 =
`√(1409-1400cos36.9)` ≈ 17 ( nearest whole number )