Three vectorsa,bandcare each 50m long and lie in the x-y place. Their directions relative to the positive x axis are 30 degree, 195 degree and 315 degree respectively. what are the magnitude and angle ofa + b + c, and ofa - b + c. What are the magnitude and angle of a fourth vectordsuch that(a + b) - (c + d)= 0.

I took the angle between the two vectors a and b as 195 - 30 = 165 and tried to apply parallelogram law of addition foraandb. andccould be added toa + b.

Is the method correct? The problem is I am not able to do anything with the angle 165 degree.

How to do this problem. Any help?

Advance thanks