Force Equilibrium in Vectors Steps:

• Resolve the two given forces into x- and y-components using trigonometry.
• Sum the x-components and y-components to find the resultant force vector.
• The third force must have magnitude equal to the resultant but opposite direction for net force zero.
• Calculate the angle of the third force from the negative resultant direction.

Why B is correct:

• The 15° angle opposes the resultant direction exactly, satisfying vector equilibrium (sum of forces = 0).

Why the others are wrong:

• A: Incorrect angle; does not align with resultant opposition.
• C: Wrong magnitude (55 N); resultant is different value.
• D: Mismatched magnitude and angle; 65 N at 16° does not balance components.

Final answer: B