Each side of a rectangular regular polygon is 2.5 cm in length.The perimeter of the polygon is 12.5 cm. How many sides does the polygon have? 

Given:

Each side of  the polygon = 2.5 cm

Perimeter of  the polygon = 12.5 cm

Let the number of sides of the polygon = n

We also know that perimeter of a polygon =  n length of each side

Therefore, putting he value of perimeter in above equation , we get

Hence, number of sides of the given polygon is 5.