Xiaooula zhigai sheepfold

Little Euler's father decided to build a new sheepfold. He measured a rectangular piece of land with a ruler, 40 meters long and 15 meters wide. He calculated that the area is exactly 600 square meters, with an average of 6 square meters per sheep. When he was ready to start construction, he found that his materials were only enough for the fence of 100 meters, which was not enough at all. If the sheepfold is 40m long and15m wide, then its circumference is110m. Father felt embarrassed, but little Euler told his father that all he had to do was move the stake in the sheepfold a little. He shortened the original side length of 40 meters to 25 meters centered on the stake. The original side length15m is extended, and10m is increased to 25m. In this way, the original planned sheepfold has become a square with a side length of 25 meters. My father built a fence according to the sheepfold designed by little Euler. 100 meter long fence is really enough, and the area is also enough, and it is a little bigger. Father felt very happy. Later, Euler became a famous mathematician in the history of mathematics