I need help. This month, Judy has checked out 20 books from the library, and Four-fifths of them were biographies. Which expression can be used to determine the number of biographies Judy checked out? a.20 divided by four-fifths b. 20 times four-fifths c. Four-fifths divided by 20 d. Five-fourths divided by 20

20*(4/5)

Step-by-step explanation:

The expression you will use is :

20*(4/5) = 80/5 = 16

16 is 80 percent of 20 wich equals 4 fifths that's true

isaiah walks 3 miles due north, turns and then 5 miles due east. how far is he from his starting point?

a^2 + b^2 = c^2

let c = distance from starting point.

(3)^2 + (5)^2 = c^2

9 + 25 = c^2

34 = c^2

sqrt{34} = sqrt{c^2}

sqrt{34} = c

the answer is  

a.

4,624π mm2

step-by-step explanation: