19. Perimeter of rectangle = 2(l + b)
l = 25m
b = 16m
Perimeter of rectangular park = 2 (25 + 16)
= 50 + 32
= 82m
Perimeter of square park = 82m
(given that, perimeter of rectangular and square park are equal)
Perimeter of square = 4a
4a = 82
a = 82/4
a = 20.5m
Area of square park = a²
= 20.5²
= 420.25m²
20. Perimeter of regular hexagon = 6a
a = 2.5
6a = 6 × 2.5
= 15cm
21. Perimeter of regular decagon = 10a
a = 8
10a = 10 × 8
= 80cm