In the given right triangle $\triangle ABC$:

1. Hypotenuse: The longest side opposite the right angle is $AB$.
2. Legs: The two shorter sides forming the right angle are:
   • $AC$ (vertical leg).
   • $BC$ (horizontal leg).

Would you like a detailed explanation about these labels or how to apply the Pythagorean theorem to this triangle?

Related Questions:

1. What is the relationship between the sides $AB, BC,$ and $AC$ using the Pythagorean theorem?
2. How can the altitude (the black line) divide $\triangle ABC$ into smaller triangles?
3. What geometric properties are preserved in the smaller triangles created by the altitude?
4. Can the altitude's length be calculated if the lengths of $AB, BC,$ and $AC$ are known?
5. How does the area of $\triangle ABC$ relate to its base and height?

Tip:

The hypotenuse is always the side opposite the right angle and is the longest side of any right triangle.