Xianjing park has a circular fountain with a diameter of 12 meters. There is a circle of stainless steel guardrail 0.5 meters outside the fountain. How long is the guardrail at least?

Xianjing park has a circular fountain with a diameter of 12 meters. There is a circle of stainless steel guardrail 0.5 meters outside the fountain. How long is the guardrail at least?

3.14×(12+0.5×2)
=3.14×13
=40.82 M