Which concept can be used to prove that the diagonals of a parallelogram bisect each other?

Afarmer sells 9.5 kilograms of apples and pears at the farmer's market. 4/5 of the weight is the apples and the rest is the pears. how many kilograms of pears did she sell at the farmers market

The number of fish in a lake can be modeled by the exponential regression equation y=14.08 x 2.08^x where x represents the year

Anyone? 15m is what percent of 60m; 3m; 30m; 1.5 km?