M2 triangle of forces

In the diagram you're asked to find Ta and Tb....given that I do know the angles between Ta and the horizontal and Tb and the horizontal, why couldn't I split the triangle into two right-angled triangles to work out the tensions? Apparently you cannot assume that the force 5g is constant along the side shown therefore all the sides would become Unknown if you made 2 triangles? Why is that true?


Posted from TSR Mobile

Why would you want to split the triangle? It's already a right-angled triangle.