Let the name of the parallelogram be ABCD, the two adjacent sides of the parallelogram be AB and AD. AB=14 and AD= 6. The shorter diagonal of parallelogram is BD. The angle between AB and AD is 60.
In triangle ABD, according to the cosine rule,
BD^2=AB^2+AD^2-2(AB)*(AD) cos(60)
= 14^2+6^2-(2)14)(6)(0.5)
=196+36-84
= 232-84
=148
BD^2=148
BD=12.1655
So the length of the shorter diagonal is 12.1655 unit.
