呎
(由英尺跳轉過來)
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唐字寫如兩呎四吋,英文two feet and four inches。減筆用單撇′代呎,雙撇″代吋,所以就寫成2′−4″、2′ 4″或者2′4″。國際上,亦會以ft.代呎。
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一九五九年以前,美國同英國,標準有啲唔同。一八九三年,美國定制係,一米有卅九又百份之卅七呢。而英國定制,係以碼爲標準,之但係,英聯邦之間都有啲唔同。[1]英國國立物理實驗室(National Physical Laboratory),一九六四年制度定,一碼係千萬份之九百一十四萬三千九百六九米[2]。所以推算一呎係千萬分之三百零四萬七千九百九十米。
一九五九年七月一號,美國同英聯邦,制定一碼做萬分之九千一百四十四米,此爲萬國英制。自此,一呎定爲萬分之三千零四十八米。咁比舊時美國定制,短百萬分之二,又比舊時英國定制,長千萬分之十七。[3]
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- ↑ See, for example, Report on the Comparisons of the Parliamentary Copies of the Imperial Standards with the Imperial Standard Yard and the Imperial Standard Pound and with each other during the Years 1947 to 1948 (H.M.S.O., London, 1950). Report on the Comparisons of the Parliamentary Copies of the Imperial Standards with each other during the Year 1957 (H.M.S.O., London, 1958).
- ↑ Bigg, P. H.; Anderton, Pamela (1964), "The United Kingdom standards of the yard in terms of the metre", Br. J. Appl. Phys., 15: 291–300, doi:10.1088/0508-3443/15/3/308 .
- ↑ "On what basis is one inch exactly equal to 25.4 mm? Has the imperial inch been adjusted to give this exact fit and if so when?". National Physical Laboratory. 喺2010-07-13搵到.