A husband and wife take turns pulling their child in a wagon along a horizontal sidewalk. Each exerts a constant force and pulls the wagon through the same displacement. They do the same amount of work, but the husband's pulling force is directed 58? above the horizontal, and the wife's pulling force is directed 38? above the horizontal. The husband pulls with a force whose magnitude is 72 N. What is the magnitude of the pulling force exerted by his wife?