In an equilateral triangle the sides are 14sqrt7. find the length of the altitude

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?

At noon a tank contained 10cm water. after several hours it contained 7cm of water. what is the percent decrease of water in the tank?

Corresponding angles are a. always b. sometimes c. never congruent