The value of Z is 42.34.
According to the Law of Cosines, the cosine of angle Z is equal to:
Cos = 17/23
Cos = 0.739
The value of Cos = 0.739 is 42.34.
So, According to the image, the cosine of angle Z is equal to 42.34. Rounding to the nearest hundredth, the answer is 42.34.