Aparallelogram has side lengths of 13 and 17 and an angle that measures 64°. law of cosines: a2 = b2 + c2 – 2bccos(a) what is x, the length of the diagonal, to the nearest whole number? 16 18 19 21

Given that the parallelogram has the dimensions given above, the value of x can be calculated using cosine rule as follows;
a^2=b^2+c^2-2bcCosA
thus;
x^2=13^2+17^2-2*13*17*cos 64
x^2=169+289-442cos64
x^2=458-193.76
x^2=264.24
thus;
x=sqrt264.24
x=16.2555
The answer is 16

Then why is the question on here if you know the answer

The answer is 25uthere is no v in the question