3.30 Three coplanar concurrent forces act as shown. a. Calculate the moment of each force about point O that lies in the line of action of the F, force. b. Calculate the algebraic summation of the three moments about point O and determine the sense of the moment sum. c. Calculate the magnitude of the resultant and angle of inclination with the X axis. d. Compute the moment of the resultant about point O and compare with the result of part (b). Problem 3.30 X- F = 75 lb 15 F = 50 lb 90 6'-0" X F = = 25 lb