Percent change is 100%
Step-by-step explanation:
Perimeter = 2 (length + width)
= 2 (6 + 4) = 2 × 10 = 20 ft
Perimeter = 2 (12 + 8) = 2 × 20 = 40 ft
Percent Change = Final value - initial value/Initial Value × 100
= (40 - 20/20) × 100
= 1 × 100 = 100%