The Pythagorean theorem is really important for understanding right triangles. Let’s break it down:

1. What is a Right Triangle?
   A right triangle has one angle that measures $90^\circ$.

2. The Sides of a Right Triangle:
   It has three sides:

   • Hypotenuse ($c$): This is the longest side. It is the side that's opposite the right angle.
   • Legs ($a$ and $b$): These are the two shorter sides that create the right angle.

3. The Formula:
   The relationship between these sides is shown in this formula:
   $a^2 + b^2 = c^2$
   This means that if you take the lengths of the legs (side $a$ and side $b$), square them (multiply each by itself), and then add those two numbers together, you will get the square of the hypotenuse (side $c$).

4. Where is it Used?
   This theorem is helpful in many areas. People use it in architecture, engineering, and physics. It's great for figuring out distances, angles, and measurements.

So, the Pythagorean theorem is not just a math rule; it's a useful tool for solving real-world problems!