One step equations plzzz help

Franco wants to double the volume of the cone. what should he do?

How many $20 bills do you need to have to make $280

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm