Question

For each group of three forces below, determine whether the forces in each pair are pulling at right angles to each other.

12 lb, 13 lb, resultant force 19 lb, yes; 15 lb, 36 lb, resultant force 39 lb, no
12 lb, 13 lb, resultant force 19 lb, no; 15 lb, 36 lb, resultant force 39 lb, yes
12 lb, 13 lb, resultant force 19 lb, yes; 15 lb, 36 lb, resultant force 39 lb, yes
12 lb, 13 lb, resultant force 19 lb, no; 15 lb, 36 lb, resultant force 39 lb, no