What is the area of the shaded rectangle?

How to do this , and can some one explain

Which sentence uses an objective tone? we will plant the best garden of any school in the area. the new campus garden will surely be envied by other schools. a garden would provide numerous benefits to the students. you will probably agree that gardens have many benefits.

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?