Given:
In triangle XYZ, x = 27 cm, y = 79 cm and
.
To find:
The length of z.
Solution:
In triangle XYZ, using the Law of cosine, we get

Putting the given values in the above formula, we get




Taking square root on both sides.


Approx the above value to the nearest number and side length cannot be negative. So,

Therefore, the length of z is about 102 cm.