The HCF of two numbers is 18 and their product is 12960. find their LCM.

Answer

To find the LCM of two numbers given their HCF and product, we can use the relationship between HCF, LCM, and the product of the two numbers.

### Step-by-step Solution:

1. **Identify the given values**:
- HCF (Highest Common Factor) = 18
- Product of the two numbers = 12960

2. **Use the relationship between HCF, LCM, and the product of two numbers**:
- The formula states:
\[ \text{Product of two numbers} = \text{HCF} \times \text{LCM} \]
- Therefore, we can express LCM as:
\[ \text{LCM} = \frac{\text{Product of two numbers}}{\text{HCF}} \]

3. **Substitute the known values into the formula**:
- Substitute the values we have:
\[ \text{LCM} = \frac{12960}{18} \]

4. **Perform the division**:
- Calculate:
\[ 12960 \div 18 = 720 \]

5. **Conclusion**:
- The LCM of the two numbers is 720.

### Final Answer:
The LCM of the two numbers is **720**.