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
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.