With a perimeter of 36, and a known width of 5, that means the length is 13. This makes the area 65.
Perimeter = (2 x Length) + (2 x Width)Width = [Perimeter - (2 x Length)]/2= [36 -(2 x 13)]/2= (36 - 26)/2= 10/2= 5 inches
Area = Length x Width= 13 x 5 = 65 square inches