<span>y components: </span> <span>100sin30° + 80sin120° + 40sin233° + Dy = 0 </span> <span>Dy = -87.34 N </span>
<span>magnitude of D: </span> <span>sqrt[(-22.53)² + (-87.34)²] </span> <span>90.2 N </span>
<span>direction of D: </span> <span>arctan[(-87.34)/(-22.53)] </span> <span>75.5° ref, but since Dx and Dy are both negative, we know this vector is in QIV: </span> <span>360 - 75.5° = 284.5°</span>