Please help me with this

Peter measures the angles in a triangle. he finds that the angles are 95, 10 and 75. is he correct? explain your answer

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%)

The length of a rectangle plus its width is 24 cm. the area is 143 square cm. what are the length and width of the rectangle?