如图,已知∠OA 1 A 2 =∠OA 2 A 3 =∠OA 3 A 4 =∠OA 4 A 5 =…=90°,且OA 1 =A 1 A 2 =A 2 A 3 =A 3 A 4 =A 4 A 5 =…=1,S 1 表示△OA 1 A 2 的面 积,S 2 表示△OA 2 A 3 的面积,…, 细心观察图形,解答下列问题: (1)0A 2 =______,0A 3 =______,S 1 =______,S 2 =______; (2)请用含有n(n是正整数)的等式表示:OA n =______; (3)求出S 1 2 +S 2 2 +S 3 2 +…S 10 2 的值.