Two numbers are in the ratio of $3:4$ and their HCF is $88$. Find their LCM.

Let the two numbers be $3x$ and $4x$, where $x$ is their Highest Common Factor (HCF).
Given, $\text{HCF}=x=88$.
The Least Common Multiple (LCM) of $3x$ and $4x$ is given by:

$$\text{LCM}=3\times 4\times x=12x$$

Substitute the value of $x$:

$$\text{LCM}=12\times 88=1056$$