Below is an instruction that describes a task. Write a response that appropriately completes the request in French. Please answer in French.

### Instruction:
 Cole wants to fence his backyard on three sides. His backyard is 9 feet along the sides and 18 feet along the back. The neighbor behind him agreed to pay for half of their shared side of his fence, and the neighbor on his left agreed to pay for a third of their shared side. Fencing costs $3 per foot. How much does Cole have to pay for the fence?


### Response:
 Cole doit payer 3 * 9 = 27 $ pour un côté de la clôture latérale.
Pour la clôture latérale partagée, il doit payer les deux tiers de 27, donc il doit payer 27 * 2 / 3 = 18 $.
La clôture arrière partagée lui coûtera 27 * 1 = 27 $.
Donc, il doit payer 18 + 27 + 27 = 72 $ pour toute la clôture.