Question

如图 , 等边 △A1C1C2 的周长为 1, 作 C1D1⊥A1C2 于 D1, 在 C1C2 的延长线上取点 C3, 使 D1C3=D1C1, 连接 D1C3, 以 C2C3 为边作等边 △A2C2C3; 作C2D2⊥A2C3 于 D2, 在 C2C3 的延长线上取点 C4, 使 D2C4=D2C2, 连接 D2C4,以 C3C4 为边作等边 △A3C3C4;… 且点 A1,A2,A3,… 都在直线 C1C2 同侧 , 如此下去 , 则 △A1C1C2,△A2C2C3,△A3C3C4,…,△AnCnCn+1 的周长和为_______．（n≥2，且 n为整数）.(面积之和？)

Answer 1