平行四邊形、三角形、梯形和多邊形的面積,你懂得計算嗎? 嘗試用這個 App 來考驗自己,看看自己是否真正掌握計算平行四邊形、三角形、梯形和多邊形面積的公式吧! Do you know how to calculate the areas of parallelograms, triangles, trapeziums and other polygons? This app will help you find out if you have mastered it!