PLease help :( An acute' s angel measure
A. exactly 90
B. between 0 and 90
C. between 90 and 180

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%)