Help please!! I have 20 min left. Brainliest to correct The sum of the base and the height of a triangle is 30 cm. Find the dimensions for which the area is a maximum

The triangle with maximum area has a height of __cm and a base of __cm

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%)