The SAS (Side-Angle-Side) criterion is a method for proving the similarity of two triangles based on the relationships between their sides and an included angle. According to the SAS criterion:
- Proportional Sides: If two sides of one triangle are proportional to two sides of another triangle, and the included angles (the angle between those two sides) are equal, then the triangles are similar.
This relationship can be summarized as follows:
- Let triangle \( ABC \) and triangle \( DEF \).
- If \( \frac{AB}{DE} = \frac{AC}{DF} \) and \( \angle A = \angle D \), then triangle \( ABC \sim triangle DEF \).
Using this criterion allows us to establish that the corresponding angles in the two triangles are congruent, which is a key characteristic of similar triangles. Thus, SAS is a reliable way to demonstrate similarity when dealing with triangles.
In summary, if you can show that two pairs of sides are in proportion and the included angle is equal, the triangles are similar according to the SAS criterion.