The roster form of a set is the elements listed inside brackets { }.
In this case it is easy to visualize A - B directly of the Venn diagram: when you subtract from A those elements that are also in B, the result is A - B = {4, 11, 14}.
Now take into account tha (A - B)' is the complement of (A - B), this is all the elements that are not in A - B.
Being A - B = {4, 11, 14} then to show (A - B)' you just have to list all the elements that are on the figure except 4, 11 and 14.
The result, in roster form, is (A - B)' = {1, 2, 3, 5, 6, 7, 8, 9, 10, 12, 13}
Angle R can be solved using the inverse sine button on a calculator. Sine is y/r so opposite leg over the hypotenuse. For r, the opposite leg is 5cm and the hypotenuse is 13. The inverse sin button looks like sin^-1. Punch that in the calculator (make sure in degree mode). Punch the inverse sin and then 5/13 and you should get 22.62°
