B. 2) Three forces act on a point: 3 N at 0°, 4 N at 90°, and 5 N at 217°. What is the net force?

Call the 3N force a Y component and the 4N force an X component.

Then we use the cosine of 217° times 5 and that equals -3.9931775 X component.

Sine of 217° times 5 equals -3.009075116 and that is the Y component.

Add 'em:
X = 4 - 3.9931775 = 0.0068225
Y = 3 - 3.009075116 = -0.009075116

Now use the Pythagorean formula to find the resultant force and angle.
Y/X = tanΘ = -1.330174569 and Θ = -53°
X^2 + Y^2 = C^2 and C = 0.0113536N