Let The origin of coordinates the tree r1 = vector position of the child 1. r2 = vector position of the child 2 Child 1: r1 = (12i + 12j) Child 2: r2 = (-18i + 11j) The scalar product will be given by: r1.r2 = ((12) * (- 18)) + ((12) * (11)) = - 84 The scalar product of their net displacements from the tree is -84m ^ 2