If it could be explained, that would help alot

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.

In the diagram, a building cast a 35-ft shadow and a flagpole casts an 8-ft shadow. if the the flagpole is 18 ft tall, how tall is the building? round the the nearest tenth.

You eat $0.85 for every cup of hot chocolate you sell. how many cups do you need to sell to earn $55.25