To find the reference number for $t = 3.6$, we can use the concept of reference angles in trigonometry. The reference angle is the acute angle formed by the terminal side of an angle $t$ and the horizontal axis (x-axis). Here's how you can find the reference number based on the quadrant where $t$ is located.

However, I assume by reference number, you're referring to the reference angle in radians or degrees. Let me know if it's something else, and I'll adjust the explanation.

1. If $t$ is in Quadrant I: The reference angle is the angle itself.
2. If $t$ is in Quadrant II: The reference angle is $\pi - t$.
3. If $t$ is in Quadrant III: The reference angle is $t - \pi$.
4. If $t$ is in Quadrant IV: The reference angle is $2\pi - t$.

For $t = 3.6$ radians:

• This is between $\pi$ (which is approximately 3.14) and $2\pi$ (which is approximately 6.28), so $t$ lies in Quadrant III.
• The reference angle $\theta_{\text{ref}} = t - \pi = 3.6 - 3.14 = 0.46$ radians.

Thus, the reference number (reference angle) for $t = 3.6$ radians is approximately 0.46 radians.

Would you like more details on reference angles? Here are five questions to further explore the topic:

1. How do reference angles help in solving trigonometric problems?
2. What are the reference angles for other common angles, like $t = 2.5$ or $t = 4.2$?
3. Can reference angles be used in both degrees and radians?
4. How do reference angles relate to the unit circle?
5. How does the quadrant of an angle affect its trigonometric functions?

Tip: Always visualize your angle on the unit circle to better understand where the terminal side lies and how the reference angle is calculated.