數學果d解釋既英文

括號內的為簡寫

1.已證 proved (proved)
2.公共角 common angle (common ∠)
3.公共邊 common side (common side)
4.三角形內角和 angle sum of triangle (∠ sum of △)
5.對頂角 vertically opposite angles (vert. opp. ∠s)
9.等腰三角形底角相等
the base angles of an isosceles triangle equal (base ∠s, isos. △)
10.三角形外角 exterior angles of triangle (ext. ∠s of △)
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如果已知兩條平行線(eg. AB//CD)：
6.同位角相等 the corresponding angles equal (corr. ∠s, AB//CD)
7.內錯角相等 the alternate angles equal (alt. ∠s, AB//CD)
8.同旁內角互補 the interior angles are supplementary (int. ∠s, AB//CD)

如要證明兩直線平行：
6.同位角相等 the corresponding angles (corr. ∠s equal)
7.內錯角相等 the alternate angles equal (alt. ∠s equal)
8.同旁內角互補 the interior angles are supplementary (int. ∠s supp.)