To find the reference angle of $105^\circ$, we first need to understand that the reference angle is the acute angle (less than $90^\circ$) between the terminal side of the given angle and the x-axis.

Since $105^\circ$ is in the second quadrant (between $90^\circ$ and $180^\circ$), the reference angle is calculated as:

$\text{Reference angle} = 180^\circ - \text{given angle}$

For $105^\circ$:

$\text{Reference angle} = 180^\circ - 105^\circ = 75^\circ$

So, the reference angle of $105^\circ$ is $75^\circ$.

Would you like further details or clarifications?

Here are 5 related questions:

1. How do you find the reference angle for an angle in the third quadrant?
2. What is the reference angle of $-60^\circ$?
3. How do reference angles relate to trigonometric functions?
4. How do you find the reference angle for an angle greater than $360^\circ$?
5. What is the reference angle of $220^\circ$?

Tip: Remember, the reference angle is always positive and less than $90^\circ$.