歷屆試題講解---**Question Stem:** 如右圖，△ABC 中，直線 L 為 BC 的中垂線且分別交 AB、BC 於 P、Q 兩點，若 ∠A=20°, ∠B=35°, AC=7, AB=10, 則 PB=? **Options:** (A) $\frac{51}{20}$ (B) $\frac{20}{7}$ (C) $\frac{24}{5}$ (D) $\frac{25}{6}$ **Chart/Diagram Description:** * **Type:** Geometric figure. * **Main Elements:** * A triangle labeled ABC. Point A is the top vertex, Point B is the left base vertex, and Point C is the right base vertex. * A line labeled L, which is shown as a vertical line segment. * Line L intersects the side BC at point Q. Line L appears to be perpendicular to BC at Q. * Line L intersects the side AB at point P. P is located on the line segment AB. * The labels A, B, C, L, P, and Q are present at their respective points/line.