Question

Two forces 5N and 4N are inclined to each other at 30°.find the resultant force by parallel method

Answer 1

you mean parallelogram?

If you let the 5N force be directed in the +x direction, then the resultant is
<5,0> + <4cos30°,4sin30°>
= <5+2√3, 2>
or, the magnitude r is
r^2 = 5^2 + 4^2 - 2*5*4*cos150°
and the angle θ between them is such that
tanθ = 2/(5+2√3)