Question

Find the length of the third side.

Answer 1

296.5

Explanation:

Let a = 217, b = 355, B = 86°, find c.

Use cosine law:

`b^2=a^2+c^2-2ac\cos(B)\\355^2=217^2+c^2-2*217*{c}*cos(86)\\126,025=47,089+c^2-30.274c\\c^2-30.274c-78,936=0\\c=(30.274\pm√(30.274^2+4*78936))/(2)\\c=(30.274+√(316660))/(2)=296.5`