The area of square A is 49 cm^{2}. The width
of rectangle B is the
side length of square A. The length of rectangle B is twice the side length of
square A. The side length of square C is thrice the width of rectangle B. What
is the difference between the area of the square C and the area of rectangle B?

The difference between the area of the square C and
the area of rectangle B is cm^{2}.

The area of square A is 49 cm^{2}.

Therefore, the side length of square A is 7 cm^{2}.

Width of rectangle B

Side length of square A

7 units 7 cm

1 unit 7 cm ÷ 7 = 1 cm

Width of rectangle B ：3 units = 3 × 1 cm = 3 cm

Length of rectangle B = 2 × 7 cm = 14 cm

Area of rectangle B = 3 cm × 14 cm = 42 cm^{2}.

Side length of square C = 3 × 3 cm = 9 cm

Area of square C = 9 cm × 9 cm = 81 cm^{2}.

81 cm^{2 }- 42 cm^{2 }= 39 cm^{2}.

The difference between the area of the square C and
the area of rectangle B is 39 cm^{2}.