Answer:
35 cm
Step-by-step explanation:
As shown in the image attached, the A large rectangle is made by joining three identical small rectangles,
The width of one small rectangle is x cm and the length of one small rectangle is 2x cm. Therefore the perimeter of the small rectangle is given as:
2(length + width) = Perimeter
2(2x + x) = 21
2(3x) = 21
6x = 21
x = 21/6 = 3.5 cm
x = 3.5 cm
From the image attached, the width of the large rectangle is 2x (x + x) and the length is 3x (2x + x). Therefore, the perimeter of the large rectangle is:
2(length + width) = Perimeter
2(3x + 2x) = Perimeter
Perimeter = 2(5x)
Perimeter = 10x
Perimeter = 10(3.5)
Perimeter = 35 cm
