Side-Angle-Side Similarity

If an angle of a triangle is congruent to an angle of another triangle and if the included sides of these angles are proportional, then the two triangles are similar .

If $\angle C\cong \angle R\text{and}\frac{BC}{QR}=\frac{AC}{PR}$ ,

then the triangles $\Delta ABC\text{and}\Delta PQR$ are similar.