What is the length of side (in cm), if perimeter of a regular octagon is 120 cm ?

Answer

To find the length of a side of a regular octagon when the perimeter is given, follow these steps:

### Step-by-Step Solution:

1. **Understand the properties of a regular octagon**: A regular octagon has 8 equal sides.

2. **Identify the given information**: The perimeter of the regular octagon is given as 120 cm.

3. **Set up the equation for the perimeter**: The formula for the perimeter (P) of a regular octagon can be expressed as:
\[ P = 8a \]
where \(a\) is the length of one side.

4. **Substitute the known perimeter into the equation**:
\[ 8a = 120 \text{ cm} \]

5. **Solve for \(a\)**: To find the length of one side, divide both sides of the equation by 8:
\[ a = \frac{120}{8} \]

6. **Calculate the value**:
\[ a = 15 \text{ cm} \]

7. **State the final answer**: Therefore, the length of each side of the octagon is 15 cm.

### Final Answer:
The length of the side of the octagon is **15 cm**.

---