(a) We know that,

Perimeter of square = 4 × Side of square

= 4 × 25 cm

= 100 cm

(b) We know that,

Perimeter of rectangle = 2 × (l + b)

Here, l is 40 cm and b is 10 cm.

= 2 × (40 + 10)

= 2 × (50)

= 100 cm

(c) We know that,

Perimeter of rectangle = 2 × (l + b)

Here, l is 30 cm and b is 20 cm.

= 2 × (30 + 20)

= 2 × (50)

= 100 cm

(d) We know that,

Perimeter of triangle = Sum of all sides

= 30 + 30 + 40

= 100 cm

The inference