SOLUTION: If a triangle has one side of 10 cm and a second side of 20 cm and an included angle of 30 degrees, find the length of the third side. I used law of cosines and came out with

Algebra ->  Triangles -> SOLUTION: If a triangle has one side of 10 cm and a second side of 20 cm and an included angle of 30 degrees, find the length of the third side. I used law of cosines and came out with       Log On


   



Question 780431: If a triangle has one side of 10 cm and a second side of 20 cm and an included angle of 30 degrees, find the length of the third side.

I used law of cosines and came out with the answer of 199.1 cm..which doesn't seem porportional to the other 2 lengths..

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
If a triangle has one side of 10 cm and a second side of 20 cm and an included angle of 30 degrees, find the length of the third side.
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199 is too long.
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s^2 = 10^2 + 20^2 - 2*10*20*cos(30) = 500 - 400*sqrt(3)/2
s =~ 12.393 cm