Explain how similar objects and proportions are related. it's talking about polygons in geometry

Related sides the the same ratio so if I have a square with side length 10 and a similar one with side length of 5 the ratio is 1/2 when going from big to small or 2/1 when going small to big.  This is true for all sides.  This allows you to find missing sides using proportions.  

mr. flanders’ class sold 47 doughnuts and   mr. rodriquez’s class sold 38 cartons of milk

step-by-step explanation:

let x be the number of doughnuts sold by mr. flanders’ class and y be the number of cartons sold by mr. rodriquez’s class.

1. together, the classes sold 85 items, then

x+y=85.

2. both classes earn earned $104.49 for their school. if doughnuts were sold for $1.35 each, then x doughnuts costed $1.35x. if cartons of milk were sold for $1.08 each, then y cartons costed $1.08y. hence,

1.35x+1.08y=104.49.

3. solve the system of two equations: