Mathematics for IGCSE & O level - Mensuration (Section 10 - No. 12)
How do you find the perimeter of a 2-D shape?
Multiply all the sides
Add up the length of all the sides
Subtract the area of the shape
Divide the area of the shape by 2
Paliwanag
The perimeter is found by summing the lengths of all the sides of the shape.