Answer:
100yd
Step-by-step explanation:
Let the width of the rectangle be x yd
Length will be 4x yd
Area = Length × width
400yd² = 4x(x)
4x² = 400yd²
Dividing by 4 throughout gives;
x² = 100 , x = 10yd
So x (width) = 10yd
Length = 4(10) = 40yd
Perimeter = 2( length + width)
Perimeter = 2(40 + 10) = 2(50) 100yd
