I am a 2 dimensional shape that had 5 obtuse angles

Of the 304 people who attended a school play, 5/8 were students. how many of the people who attended were students.

Astudent must have an average on five test that is greater than it equal to 80% but less than 90% to receive a final grade of b. devon's greades on the first four test were 78% 62% 91% and 80% what range if grades on the fifth test would give him a b in the course? ( assuming the highest grade is 100%)

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?