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类比平面几何中的勾股定理:若直角三角形ABC中的两边AB、AC互相垂直,则三角形三边长之间满足关系:AB2+AC2=BC2.若三棱锥A﹣BCD的三个侧面ABC、ACD、ADB两两互相垂直,则三棱锥的三个侧面积S1,S2,S3与底面积S之间满足的关系为____
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S12+S22+S32

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    It was Mother's Day morning last year and I was doing my shopping at our local supermarket with my five-year-old son, Teayson. As we were leaving, we found that only minutes earlier an elderly woman had fallen over at the entrance and had hit her bead on the concrete. Her husband was with her, but there was blood everywhere and the woman was embarrassed and clearly in shock.

    Walking towards the scene, Tenyson became very upset about what had happened to the couple. Ile said to me. “Mums it's not much fun falling over in front of everyone.”

    At the front of the supermarket a charity group had set up a stand selling cooked sausages and flowers to raise funds. Tenyson suggested that we should boy the lady a flower. “It will make her feel better,” he said. I was amazed that he'd come up such a sweet idea. So we went over to the flower seller and asked her if we could buy a flower for the lady to cheer her up. “Just take it,” she replied. “I can't take your money for such a wonderful gesture.”

    By now paramedics(救援人员) had arrived, and were attending the injured woman. As we walked up to her, my son became intimidated by all the blood and medical equipment. He said he was just too scared to go up to her.

    Instead I gave the flower to the woman's husband and told him. “My son was very upset for your wife and wanted to give her this flower to make her feel better.”

    At that, the old man started crying and said, “Thank you so much, you have a wonderful son, Happy Mother's Day to you.”

The man then bent down and gave his wife the flower, telling her who it was from. Though badly hurt and shaken, the old lady looked up at Tenyson with love in her eyes and gave him a little smile.