When working with right-angled triangles, students often make some common mistakes with trigonometric ratios. Here are a few to watch out for:

1. Mixing Up Ratios: It’s really important to know what each ratio means! For a triangle with angle $\theta$:

   • Sine: $\sin(\theta) = \frac{\text{opposite side}}{\text{hypotenuse}}$
   • Cosine: $\cos(\theta) = \frac{\text{adjacent side}}{\text{hypotenuse}}$
   • Tangent: $\tan(\theta) = \frac{\text{opposite side}}{\text{adjacent side}}$

2. Choosing the Wrong Triangle: Always make sure you’re looking at the right triangle that matches the angle you’re working with.

3. Ignoring the Units: When you’re solving real-world problems, don’t forget to keep your units the same!

By being careful with these points, you'll get the hang of trigonometric ratios in no time!