You can have same perimeter but different area for 4-sided rectilinear figures (i.e rectangles and squares)

What we want for the biggest possible area is to make the length and breadth equal (i.e a square)

Since all 4 sides are equal,

1 side = 20 m ÷ 4 = 5 m

5 m × 5 m = 25 m²

The area of D is the largest as it is the only square.

Basically, you cut your square D into 25 smaller squares so each square has an area of 1 m²

Other possible length and breadth pairings :

length = 6 m, breadth = 4 m
Perimeter also = 6 m + 6 m + 4 m + 4 m =
20 m

But area = 6 m × 4 m = 24 m²



length = 7 m, breadth = 3 m
Perimeter also = 6 m + 6 m + 4 m + 4 m = 20 m

But area = 7 m × 3 m = 21 m²



length = 8 m, breadth = 2 m
Perimeter also = 8 m + 8 m + 2 m + 2 m = 20 m

But area = 8 m × 2 m = 16 m²



length = 9 m, breadth = 1 m
Perimeter also = 9 m + 9 m + 1 m + 1 m = 20 m

But area = 9 m × 1 m = 9 m²



length = 9.5 m, breadth = 0.5 m
Perimeter also = 9.5 m + 9.5 m + 0.5 m + 0.5 m = 20 m

But area = 9.5 m × 0.5 m = 4.75 m²



These are all smaller than the square's area of 25 m²

Thank you so much.