Write a function that takes as input the atomic coordinates of 3 atoms and calculates the corresponding angle between them.

Use it to calculate all 3 H-N-H angles (in degrees) for a molecule of ammonia - coordinates are pre-loaded below.

Print the average angle

import numpy as np

ammonia_coord = np.array([[ -0.002 , -0.001 , -0.070], # nitrogen

[ -0.940 , 0.000 , 0.319], # hydrogen 1

[ 0.471 , -0.812 , 0.321], # hydrogen 2

[ 0.469 , 0.819 , 0.322]]) # hydrogen 3