1. The problem statement, all variables and given/known data First of all I will have to apologize if this in in the wrong forum. It is a 1st year engineering mechanics problem. I am having an issue solving a secondary part of a question. The first part of the question has asked me to both graphically and numerically determine a resultant of three forces acting on an object, with magnitude and angles for all given. This was straightforward. I am now being asked to determine a fourth Force such that the resultant R of all the four forces will be vertical (90 degrees) and has a magnitude of 750 N. I have done this question graphically, but am wondering how I go about doing it numerically ..just buy using trig etc. thanks much, 3. The attempt at a solution i have thus far determined that my previous resultant force was 821 N at 87 degrees North of East. I have therefore now said that my resultant is going to have to = 750 N so 750 = (sum Fx + sum Fy)^(1/2). I am just unsure how I would go about getting two unkowns from this methodology, the X component and Y component of the unkown vector..