The SSS (Side-Side-Side) similarity rule is really simple! Here’s what you need to know:

1. Comparing Triangles: When you have two triangles, you can look at their sides.

2. Matching Sides: The lengths of all three sides of one triangle must match the lengths of the sides of the other triangle in a certain way.

   So, if triangle ABC has sides labeled $a$, $b$, and $c$, and triangle DEF has sides labeled $d$, $e$, and $f$, you want to check this:

   $\frac{a}{d} = \frac{b}{e} = \frac{c}{f}$

3. Final Check: If all three pairs of sides are proportional, then the triangles are similar!

This means they look the same but might be different sizes—cool, right?