When does the fall equinox occur in the northern hemisphere

What is the length x of the side of the triangle below? (hint: use the cosine function)

Edward tolman explained the results of his study by theorizing that the rats were learning about the maze during every trial but they a. were agitated because other groups were getting reinforcement b. could not remember how to demonstrate it without reinforcement c. were not motivated to demonstrate it without reinforcement d. seemed to be too lazy to actually work without reinforcement

Aregion of space in which a measurable gravitational force is indicated by the force exerted on a test mass is called