Use the inverse sine function on a calculator.
arcsin (0.88) = 1.08 radians
Consider the expression 
This expression contains two terms with
group them:

Now simplify term 
Now 
This expression is defined for all x.
Answer: 65200
7 - 1 = 6 x 11700 = 70200 - 5000 = 65200
If the width is 28 inches, then divide that by 4 and you get 7. You multiply that by 5 to get the length. That would be 35. Just to check, you know that the width 28 and length 35 are in ratio 4:5 if you divide by 7. The perimeter would be 2(35+28)=63*2=126. So the perimeter is 126. The area would be 35*28 which is 980. To sum up, the answers are as follows.
Length: 35 in
Perimeter: 126 in
Area: 980 inches squared.
Rise over run, -2/4 or -1/2 so the slope is -1/2 or -0.5. (View picture) And the slope is negative because you are going down wards \ and the "rise" is going down.