Hi there!
[tex]\huge\boxed{\text{22 cm}}[/tex]
We know that:
Area of a rectangle = l × w
The areas are the same, so:
3x · 4 = 6(3x - 2.5)
Simplify:
12x = 18x - 15
Solve for x:
15 = 6x
x = 2.5
Plug in this value of x to find the perimeter of rectangle B:
P = 2l + 2w
l = 6
w = 3(2.5) - 2.5 = 5
P = 2(6) + 2(5) = 22 cm
