Zeda described four triangles as shown below: Triangle P: Two angles measure 50°. Triangle Q: All sides have length 13 cm. Triangle R: Two sides have length 3 cm, and the included angle measures 60°. Triangle S: Base has length 5 cm, and base angles measure 30°. Which triangle is not a unique triangle?

Triangle P is not a unique triangle because having two angles that measure 50° would give multiple possibilities for the third angle, making it not unique.