The reference angle is the positive acute angle formed between the terminal side of the given angle and the x-axis. Here's how we find the reference angle for $315^\circ$:

1. The angle $315^\circ$ is in the fourth quadrant.
2. To calculate the reference angle for angles in the fourth quadrant, subtract the angle from $360^\circ$: $\text{Reference Angle} = 360^\circ - 315^\circ = 45^\circ$

Final Answer:

The reference angle for $315^\circ$ is $45^\circ$.

Would you like further explanation or have any other questions?

Here are 5 related questions for further learning:

1. What are reference angles and why are they important in trigonometry?
2. How do you find reference angles for angles in the second quadrant?
3. What are the trigonometric values of the angle $315^\circ$ compared to its reference angle $45^\circ$?
4. How does the concept of reference angles apply to radian measure?
5. What is the difference between coterminal angles and reference angles?

Tip: Always visualize reference angles on the unit circle to strengthen your understanding!