Geometry

Question Analysis：
This problem involves setting up and solving a ratio relationship between adjacent angles in a parallelogram.

Key Concept Explanation：
Key parallelogram angle properties：
• Adjacent angles are supplementary
• Opposite angles are equal

Step-by-Step Solution：
Let ∠Q = x
Then ∠P = 3x
Set up equation：
3x + x = 180 → 4x = 180 → x = 45
Find angles：
∠Q = 45°
∠P = 135°
∠R is opposite ∠P → ∠R = ∠P = 135°

Common Mistak...