Question

Suppose a triangle has two sides of the length 2and 3 and that the angle between these two sides is 60 what is the length of the third side of the triangle

Answer 1

Let the given sides be "a" and "b" and the unknown side be "c". The Law of Cosines tells you
.. c^2 = a^2 +b^2 -2ab*cos(C)
.. c^2 = 2^2 +3^2 -2*2*3*cos(60°)
.. c^2 = 7
.. c = √7 ≈ 2.6458

The third side of the triangle is √7, about 2.6458.