What is 7 7/8 dvided by 3 1/8 mixed numbers

In triangle abc segment de is parallel to the side ac . (the endpoints of segment de lie on the sides ab and bc respectively). find de, if ac=20cm, ab=17cm, and bd=11.9cm;

The graph below shows the height of a projectile t seconds after it is launched. if acceleration due to gravity is -16 ft/s2, which equation models the height of the projectile correctly?

Can somebody 1. what is the formula for finding the vertical distance between two points on a coordinate plane?