The slope would be 1.2. If they are parallel lines, they have the same slope. :)
I'm afraid it's not 11 (unless you can round the result up, but there is no mention about it).
8 + 13 + 11 + 9 + 13 = 54
54 / 5 = 10,8
Firstly you sum all the numbers and then you divide the result by the amount of the summed up numbers.
Area = length of base × altitude
34 = 8.5 × a
34 = 8.5a
a = 34/8.5
a = 4
The altitude of the corresponding side is 4 cm
The answer to your question Meowgatita15, is D.