Let a,b and c is side of a triangle where:
a = 1
b = 5
c = 11
a^2 + b^2 = c^2. if the following statement is right, then triangle have these side.
1^2 + 5^2 = 11^2
1 + 25 = 121
26 != 121 ( != means not equal to)
Therefore, triangle can't have side length of 1, 5 and 11 ft.