Answer:
296.5
Step-by-step explanation:
Let a = 217, b = 355, B = 86°, find c.
Use cosine law:
[tex]b^2=a^2+c^2-2ac\cos(B)\\355^2=217^2+c^2-2\times217\times{c}\times\cos{86}\\126,025=47,089+c^2-30.274c\\c^2-30.274c-78,936=0\\c=\frac{30.274\pm\sqrt{30.274^2+4\times78936}}{2}\\c=\frac{30.274+\sqrt{316660}}{2}=296.5[/tex]
