Answer:
8ft
Explanation:
Area of a rectangle = Length × Width = LW
Area = 128 ft²
Width = W = 2L
Hence
128 = 2L × L
128 = 2L²
Divide both sides by 2
128/2 = L²
L² = 64
Square root both sides
√L² = √64
L = 8
Therefore, the measure of the Length = 8 ft