The volume of a large tank is 210 ft3. It is 6 2/3 ft wide and 2 4/5ft high. What is the length of the tank?

The radius of the base of a cylinder is 10 centimeters, and its height is 20 centimeters. a cone is used to fill the cylinder with water. the radius of the cone's base is 5 centimeters, and its height is 10 centimeters.

Ineed me i stuck and i don’t want to get it wrong

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.