一个正多边形的每个外角是45°．
（1）试求这个多边形的边数；（2）求这个多边形内角和的度数．
（1）方法一：设这个多边形的边数为n，
得：45°n=360°，
解得：n=8．
∴这个多边形的边数为8．
方法二：多边形每一个内角为：180°-45°=135°．
设这个多边形的边数为n，
得：（n-2）×180°=135°×n，
解得：n=8．
∴这个多边形的边数为8．
（2）这个多边形内角和的度数为（n-2）×180°=（8-2）×180°=1080°．
| I graduated from a small public school in Michigan. One day, Mr. Ledy, our football coach, asked me to play football. I couldn't help__1__: me, play football? I was six feet tall and was not much__2__a hundred pounds in weight. I thought that they might just need__3__fool to increase the number of the players. However, he was persistent(坚持的) and__4__I joined the football team. That__5__to be one of my best decisions as a kid. Our worst game__6__was the one against Crystal Falls. They beat us 56 to 6. Yeah! That was a football not a basketball__7__. We played them again when we were seniors. They__8__us again but the score was much more__9__, 30 to 20. Coach Ledy would not let that __10__again. He encouraged us to beat them, to pay them back. And we did so in the last game we played before__11__. I had scored 6 points alone in the game. Coach Ledy praised me. It was a huge__12__for me. Was I a football hero? Ha! Ha! No, I couldn't__13__it without our team. The thing I learned through football was__14__. We won as a team and we__15__as a team. I think Mr. Ledy would be__16__of me if he knew that I had broken the athletic__17__at the University of Michigan. I'm__18__to him as I would not have today’s honor without him. I'll __19__life's final war with pain to win the victory; I'll seek the lights of glory wholeheartedly and I'll__20__working hard so as not to let him down. | ||||
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