Math topic中文Counting geometric figuresCount segments, angles, triangles and rectangles by reducing to ordered choices of points or lines.Learn these firstMultiplication principlePractice questions1How many pairs of parallel edges, such as AB‾\overline{AB}AB and GH‾\overline{GH}GH, or EH‾\overline{EH}EH and FG‾\overline{FG}FG, d…2下图中一共有 ___ 条线段．