The formula for perimeter depends on the shape you're dealing with. Here are some common ones:

Perimeter Formulas for Common Shapes

• Square :

Perimeter=4×side\text{Perimeter}=4\times \text{side}Perimeter=4×side

• Rectangle :

Perimeter=2×(length+width)\text{Perimeter}=2\times (\text{length}+\text{width})Perimeter=2×(length+width)

• Triangle :

Perimeter=side1+side2+side3\text{Perimeter}=\text{side}_1+\text{side}_2+\text{side}_3Perimeter=side1​+side2​+side3​

• Circle (called circumference):

Perimeter=2πr\text{Perimeter}=2\pi rPerimeter=2πr

where rrr is the radius.

If you tell me the specific shape, I can give you the exact formula!