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1、人教版六年級(jí)數(shù)學(xué)上冊(cè)132終點(diǎn)線(xiàn)終點(diǎn)線(xiàn)85.96m72.6m1.25m1.25m1.25m85.96m72.6m1.25m1.25m1.25m12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)注:注:取取3.1415985.96m72.6m第一道第一道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):72.6m72.63.14159228.08(m)85.962228.08=400(m)12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.08400注:注:取取3.1415985.96m72.6m第一道第一道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):72.6m228.08m400m第二
2、道第二道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):72.61.251.25=75.1(m)75.13.14159235.93(m)85.962235.93=407.85(m)1.25m1.25m12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.85注:注:取取3.1415985.96m72.6m第二道第二道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):75.1m235.93m407.85m第三道第三道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):75.11.251.25=77.6(m)77.63.14159243.79(m)85.962243.79=415.
3、71(m)1.25m1.25m75.1m12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.8577.6243.79415.71注:注:取取3.1415985.96m72.6m第三道第三道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):77.6m243.79m415.71m第四道第四道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):77.61.251.25=80.1(m)80.13.14159251.64(m)85.962251.64=423.56(m)1.25m1.25m77.6m12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0
4、840075.1235.93407.8577.6243.79415.7180.1251.64423.56注:注:取取3.1415985.96m72.6m第四道第四道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):80.1m251.64m423.56m第五道第五道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):80.11.251.25=82.6(m)82.63.14159259.50(m)85.962259.5=431.42(m)12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.8577.6243.79415.7180.1251.64423.5682.625
5、9.5431.42注:注:取取3.1415985.96m72.6m第五道第五道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):82.6m259.5m431.42m第六道第六道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):82.61.251.25=85.1(m)85.13.14159267.35(m)85.962267.35=439.27(m)12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.8577.6243.79415.7180.1251.64423.5682.6259.5431.4285.1267.35439.27注:注:取取3.1415985.96
6、m72.6m第六道第六道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):85.1m267.35m439.27m第七道第七道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):85.11.251.25=87.6(m)87.63.14159275.20(m)85.962275.2=447.12(m)12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.8577.6243.79415.7180.1251.64423.5682.6259.5431.4285.1267.35439.2787.6275.2447.12注:注:取取3.1415985.96m72.6m第七道第七道
7、直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):87.6m275.2m447.12m第八道第八道直徑:直徑:周長(zhǎng):周長(zhǎng):全長(zhǎng):全長(zhǎng):87.61.251.25=90.1(m)90.13.14159283.06(m)85.962283.06=454.98(m)12345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.8577.6243.79415.7180.1251.64423.5682.6259.5431.4285.1267.35439.2787.6275.2447.1290.1283.06454.98注:注:取取3.14159各跑道的起跑線(xiàn)應(yīng)該相差多少
8、米?各跑道的起跑線(xiàn)應(yīng)該相差多少米?7.85m / 7.86m7.857.867.857.867.857.857.8612345678直徑直徑(m)周長(zhǎng)周長(zhǎng)(m)全長(zhǎng)全長(zhǎng)(m)72.6228.0840075.1235.93407.8577.6243.79415.7180.1251.64423.5682.6259.5431.4285.1267.35439.2787.6275.2447.1290.1283.06454.98注:注:取取3.14159我不用算出每條跑道的長(zhǎng)度,也知道它我不用算出每條跑道的長(zhǎng)度,也知道它們相差多少米們相差多少米? ?兩條直道是一樣的,所以只需要看兩條直道是一樣的,所以只需
9、要看圓的周長(zhǎng)。圓的周長(zhǎng)是這樣算的:圓的周長(zhǎng)。圓的周長(zhǎng)是這樣算的:第一道:第一道:72.6第二道:第二道:(72.62.5) = 72.62.5第三道:第三道:(75.12.5) = 75.12.5第四道:第四道:(77.62.5) = 77.62.5第五道:第五道:(80.12.5) = 80.12.5第六道:第六道:(82.62.5) = 82.62.5第七道:第七道:(85.12.5) = 85.12.5第八道:第八道:(87.62.5) = 87.62.5每一條跑道都在每一條跑道都在上一條跑道的基上一條跑道的基礎(chǔ)上增加礎(chǔ)上增加2.52.5的長(zhǎng)度。你能算的長(zhǎng)度。你能算出出2.52.5是多少
10、是多少米嗎?米嗎?終點(diǎn)終點(diǎn)起點(diǎn)起點(diǎn)200米的跑道,每條道的長(zhǎng)度都是它米的跑道,每條道的長(zhǎng)度都是它們?nèi)L(zhǎng)的一半。們?nèi)L(zhǎng)的一半。第一條:第一條:4002=200(m)第二條:第二條:407.852=203.925(m)第三條:第三條:415.712=207.855(m)第四條:第四條:423.562=211.78(m)第五條:第五條:431.422=215.71(m)每條道相差每條道相差3.925m或或3,39m。所以起跑線(xiàn)應(yīng)依次提前約。所以起跑線(xiàn)應(yīng)依次提前約3.925m。思考:思考:200200米跑步比賽,跑道寬為米跑步比賽,跑道寬為1.251.25米,起跑線(xiàn)應(yīng)依次米,起跑線(xiàn)應(yīng)依次提前多少米?提前多少米?謝謝!謝謝!