Answer:
"Let's say it is equal to 45 degrees, or π/4. Calculate the arc length according to the formula above: L = r * Θ = 15 * π/4 = 11.78 cm . Calculate the area of a sector: A = r² * Θ / 2 = 15² * π/4 / 2 = 88.36 cm² . You can also use the arc length calculator to find the central angle or the radius of the circle. "
All you do is divide -12/20 by 4/4 which is -3/5
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.