A parallelogram 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