题干

将一张长1072毫米、宽469毫米的长方形纸,剪成面积相等的正方形,并且最后没有剩余,这些正方形的边长最大是多少?

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解:根据题意分析可知,这道题实际上是要求长方形的长和宽的最大公因数。但这道题中,长和宽的数比较大,最大公因数比较难求出,所以我们用下面的方法来求:第一步:1072÷469,余134;第二步:469÷134,余67;第三步:134÷67,没有余数。所以67是1072与469的最大公因数,即这些正方形的边长最大是67毫米。

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    It is not easy getting the attention of tourists away from the well-known white sandy beaches of Byron Bay. But in this relying Australian surf town, a solar (太阳能的)-powered train might just do a good job.

    Opening to the public in December 2017 along a 1.9-mile-long stretch (一段) of track that sat abandoned for more than a decade, the Byron Bay Rail Company has breathed new life into a pair of disused railcars dating back to the 1940s. They're now used to transport passengers between Byron Bay's central business district and the North Beach area. After remaining in service as part of a regional passenger rail network until the early 1990s, the aging railcars were out of service and sat uncared for — almost destroyed by time and unpleasant Aussie climate — in a railyard for more than 20 years. You'd never know it by looking at these nearly 70-year-old workhorses today, though: they've been decorated, equipped, topped with custom-made photovoltaic panels (定制的光电池板) and rearranged to accommodate up to 100 seated beach goers.

    It's those train-top PV panels that truly set the Byron Bay Rail Company's flagship train apart from other heritage rail restoration projects.

    Drawing additional power from a 30-kilowatt solar array (阵列) located atop the train's storage building, the tain is said to be the first in the world to be completely powered by the sun. Solar energy caught by the 6.5-kilowatt train-top solar panels is stored directly in an onboard battery system that powers motors, lighting and the like. When stopped at its home platform, the train pushes into chargers for quick battery top-offs with electricity produced by the storage building's rooftop solar array. The 77 kilowatt-hour battery can hold enough juice for 12 to 15 runs on a single charge. During long periods of cloudiness when the solar arrays don't get enough sun, the train uses the main electric network, supply using renewable energy sold by community-based service Enova Energy.

    The Byron Bay Rail Company's first-in-the-world folly solar-powered train is a good example of historic rail preservation with a 21st century development. Operating as a not-for-profit company, the Byron Bay Rail Company also expected the AU$4 million line to be a way to relieve traffic jam between downtown Byron Bay and the rapidly growing North Beach area. Really, there's no bigger unpleasant thing than sitting in bad traffic for 40 minutes trying to get to the beach.