By the Pythagoras theorem, in a right-angled triangle:

The Pythagoras theorem describes a fundamental relationship between the sides of a right-angled triangle. 1. **Identify the Sides**: In a right-angled triangle, the two sides that form the 90-degree angle are called the **legs** (let's call them $a$ and $b$). The longest side, opposite the right angle, is the **hypotenuse** ($c$). 2. **State the Formula**: The theorem states that: $$a^2 + b^2 = c^2$$ 3. **Translate to Words**: - $a^2$ and $b^2$ represent the **squares of the legs**. - The $+$ sign represents the **sum**. - $c^2$ represents the **square of the hypotenuse**. Therefore, the sum of the squares of the legs equals the square of the hypotenuse.