20 is 80% of what number?

How many $20 bills do you need to have to make $280

Solve the problem. a student earned grades of c, a, b, and a in four different courses. those courses had these corresponding numbers of credit hours: 4, 5, 1, and 5. the grading system assigns quality points to letter grades as follows: a = 4, b = 3, c = 2, d = 1, and f = 0. compute the grade point average (gpa) and round the result to two decimal places. 3.40 3.50 8.75 2.18

What is the missing reason in the proof? segment addition congruent segments theorem transitive property of equality subtraction property of equality?