人教版小學(xué)數(shù)學(xué)六年級(jí)上冊(cè)確定起跑線ppt課件.ppt

確定起跑線,人教版數(shù)學(xué)六年級(jí)（上）,1,3,2,終點(diǎn)線,85.96m,72.6m,1.25m,1.25m,1.25m,85.96m,72.6m,1.25m,1.25m,1.25m,注：取3.14159,85.96m,72.6m,第一道,直徑：,周長(zhǎng)：,全長(zhǎng)：,72.6m,72.63.14159228.08（m）,85.962228.08=400（m）,72.6,228.08,400,注：取3.14159,85.96m,72.6m,第一道,直徑：,周長(zhǎng)：,全長(zhǎng)：,72.6m,228.08m,400m,第二道,直徑：,周長(zhǎng)：,全長(zhǎng)：,72.61.251.25=75.1（m）,75.13.14159235.93（m）,85.962235.93=407.85（m）,1.25m,1.25m,72.6,228.08,400,75.1,235.93,407.85,注：取3.14159,85.96m,72.6m,第二道,直徑：,周長(zhǎng)：,全長(zhǎng)：,75.1m,235.93m,407.85m,第三道,直徑：,周長(zhǎng)：,全長(zhǎng)：,75.11.251.25=77.6（m）,77.63.14159243.79（m）,85.962243.79=415.71（m）,1.25m,1.25m,75.1m,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,注：取3.14159,85.96m,72.6m,第三道,直徑：,周長(zhǎng)：,全長(zhǎng)：,77.6m,243.79m,415.71m,第四道,直徑：,周長(zhǎng)：,全長(zhǎng)：,77.61.251.25=80.1（m）,80.13.14159251.64（m）,85.962251.64=423.56（m）,1.25m,1.25m,77.6m,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,注：取3.14159,85.96m,72.6m,第四道,直徑：,周長(zhǎng)：,全長(zhǎng)：,80.1m,251.64m,423.56m,第五道,直徑：,周長(zhǎng)：,全長(zhǎng)：,80.11.251.25=82.6（m）,82.63.14159259.50（m）,85.962259.5=431.42（m）,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,注：取3.14159,85.96m,72.6m,第五道,直徑：,周長(zhǎng)：,全長(zhǎng)：,82.6m,259.5m,431.42m,第六道,直徑：,周長(zhǎng)：,全長(zhǎng)：,82.61.251.25=85.1（m）,85.13.14159267.35（m）,85.962267.35=439.27（m）,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,注：取3.14159,85.96m,72.6m,第六道,直徑：,周長(zhǎng)：,全長(zhǎng)：,85.1m,267.35m,439.27m,第七道,直徑：,周長(zhǎng)：,全長(zhǎng)：,85.11.251.25=87.6（m）,87.63.14159275.20（m）,85.962275.2=447.12（m）,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,87.6,275.2,447.12,注：取3.14159,85.96m,72.6m,第七道,直徑：,周長(zhǎng)：,全長(zhǎng)：,87.6m,275.2m,447.12m,第八道,直徑：,周長(zhǎng)：,全長(zhǎng)：,87.61.251.25=90.1（m）,90.13.14159283.06（m）,85.962283.06=454.98（m）,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,87.6,275.2,447.12,90.1,283.06,454.98,注：取3.14159,各跑道的起跑線應(yīng)該相差多少米？,7.85m,/7.86m,7.85,7.86,7.85,7.86,7.85,7.85,7.86,72.6,228.08,400,75.1,235.93,407.85,77.6,243.79,415.71,80.1,251.64,423.56,82.6,259.5,431.42,85.1,267.35,439.27,87.6,275.2,447.12,90.1,283.06,454.98,注：取3.14159,我不用算出每條跑道的長(zhǎng)度，也知道它們相差多少米?,兩條直道是一樣的，所以只需要看圓的周長(zhǎng)。圓的周長(zhǎng)是這樣算的：,第一道：72.6,第二道：(72.62.5)=72.62.5,第三道：(75.12.5)=75.12.5,第四道：(77.62.5)=77.62.5,第五道：(80.12.5)=80.12.5,第六道：(82.62.5)=82.62.5,第七道：(85.12.5)=85.12.5,第八道：(87.62.5)=87.62.5,每一條跑道都在上一條跑道的基礎(chǔ)上增加2.5的長(zhǎng)度。你能算出2.5是多少米嗎？,終點(diǎn),起點(diǎn),200米的跑道，每條道的長(zhǎng)度都是它們?nèi)L(zhǎng)的一半。,第一條：4002=200（m）,第二條：407.852=203.925（m）,第三條：415.712=207.855（m）,第四條：423.562=211.78（m）,第五條：431.422=215.71（m）,每條道相差3.925m或3,39m。所以起跑線應(yīng)依次提前約3.925m。,思考：200米跑步比賽，跑道寬為1.25米，起跑線應(yīng)依次