Please need assistance with Vector Addition using Graphical and Analytical methods

Question

After doing an experiment on vector addition using a Horizontal force board (Gravesand Apparatus), with the need to use graphical and analytical methods of vector addition. For the Horizontal force board, the force-meters were stretched into the alignment of a letter Y; the two force-meters at the top each had a reading of 1.55 N whilst the force-meter at the bottom (equilibrant) had a reading of 1.85 N. The angle in between the junction of the “Y” was 110°. Using a sketch with a scale of 1 cm = 0.5 N for the graphical method. With that in mind, how can I use this information in the analytical method to calculate the Size and the direction of the Resultant force, using the both the Parallelogram rule and vector tangent rule?

Experiment Data:

F_A = 1.55N

F_B= 1.55 N

F_C (Equilibrant) = 1.85 N

Angle of F_A relative to X-axis = 140°

Angle of F_B relative to X-axis = 35°

Answer 1

The statements "angle of FA relative to x-axis = 140°" and "angle of FB relative to x-axis = 35° would mean that the angle between FA and FB is 105° and not 110°.

One of these measurements is not correct. Now the question is which?

As FA and FB are equal in magnitude, the Y is symmetrical so we are considering the Y axis been aligned with FC.

Graphically, using the parallelogram method, you can actually resolve the problem by successively building parallelograms between pairs of vectors and it doesn't matter which pair of forces you consider first.

Consider the FA and FB parallelogram to get the F_AB resultant. The actual geometric proof can be done showing that the resulting F_AB is aligned with FC but pointing in the opposite direction.

The parallelogram between F_AB and FC is laying flat along the line containing F_AB and FC. You can trace the vertices and thus get the magnitude and direction of the resultant vector of the F_AB and FC vectors.

Or, first build the parallelogram between FA and FC, then the parallelogram between the resultant F_AC and FB. The resultant vector is the same as in the first approach.

There is no vector tangent rule to be applied here as there is no curve any of these vectors would be tangent to.

One more mention: Newton's second law says that the system will accelerate in the direction of the net force if this net force it's not zero. If the resultant is not 0, the whole Y should have accelerated in the direction of the resultant.

So was the Y in static equilibrium or not?