Respuesta :

Step-by-step explanation:

Use law of sines.

16 / sin 39° = BC / sin 120°

BC ≈ 22.02

Greetings from Brasil...

Here we cant use calculator..... It seems that in the USA the use of a scientific calculator is allowed

Let's use Senos Law in Any Triangle

(AC/SEN B) = (BC/SEN A)

16/SEN 39 = BC/SEN 120     sen 120 = sen 60 = √3/2

16/0,63 = BC/(√3/2)

0,63BC = 16√3/2

BC = 8√3/0,63

BC ≈ 22

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