From his playhouse, a child walks 11 m east, then 7 m north, then 13 m east. What is the magnitude of the child's displacement?

This is what i found on google “according to the collision theory, the following criteria must be met in order for a chemical reaction to occur: molecules must collide with sufficient energy, known as the activation energy, so that chemical bonds can break. molecules must collide with the proper orientation.” i hope this information you.