A particle with charge q1 = +21 nC is placed on the x axis of a certain coordinate system at x = 13 cm. A particle with charge q2 = ?43 nC is placed on the y axis at y = 15 cm. Determine the magnitude (in mN) and direction (relative to the negative x-axis in degrees) of the force acting on a particle with charge q3 = +11 nC placed at the origin.