A triangle has sides A, B, and C. Sides A and B are of lengths #4# and #7#, respectively, and the angle between A and B is #(3pi)/4 #. What is the length of side C?

1 Answer
Pietro P.
Jun 1, 2016

Side C=10.1 units

Explanation:

This question can be used using the law of cosines, and equation used to figure out information regarding either side length or angle of a non right triangle. The formula is #c^2#=#a^2# +#b^2#-2(a)(b)cos(#angleC#). So plugging the info in, we get #c^2#=#4^2#+#7^2#-2(4)(7)cos(#3pi/4#). Solving this with a calculator, we get #c^2#=102.6. Squaring that values, we get the finally of 10.1 units.

P.S. I assumed that the angle was in radians.

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