Find the resultant of two vectors 7N and 8N inclined at an angle of 65 degree to each other

Answer 1

One can derive from the law of cosines:

c = sqrt[a^2 + b^2 + 2ab cos65]
= sqrt[49 + 64 + 56*0.4226] = 12.66

c is the long diagonal of the force parallelogram, i.e the resultant

One can also do it with components. The resultant of
(7 + 8 cos65)i and 8 sin65 j is
sqrt(10.381^2 + 7.251^2] = 12.66