Question

If cable AD is tightened by a turnbuckle and develops a tension of 1200 lb , determine the tension developed in cable AB.

figure: session.masteringengineering.com/problemAsset/2071868/2/Hibbler.ch3.p61.jpg

Answer 1

At the top the sum of the x force components must be zero and the sum of the y force components must be zero.
It is a trig mess but no big deal.