I saw him in the library yesterday. He a book at that moment.
——A new museum in Shenyang in May.——Great! Let's go and visit it this summer.
如下图，先沿三角尺的直角边画一条直线，再把三角尺沿着直尺平移5cm，再沿三角尺的直角边画一条直线．观察这两条直线，你发现了什么？
，则它的外接球半径R与内切球半径
之比为（ ）