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

### Instruction:
The three angles of a triangle add up to 180 degrees.  The largest angle is 5 times bigger than the smallest. The middle angle is 3 times bigger than the smallest. How many degrees is the smallest angle?

### Response:
 กำหนดให้ x เป็นมุมที่เล็กที่สุด
ผลรวมของทั้งสามมุมคือ x + 3x + 5x = 9x
ดังนั้น 9x = 180
จึง x = 20