How do i solve the proportion 4/9=10/x

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

Water flows at a steady rate from a tap. its takes 40 seconds to fill a 4 litre watering can from the tap. the rate at which water flows from the tap is halved. complete: 4 litres into cm3

Idon’t understand! use slope intercept form to solve: through: (2,5) slope= undefined