∵拱桥的跨度AB=24cm,拱高CD=8cm,
∴AD=12cm,
∴AD2=OA2﹣(OC﹣CD)2,即122=AO2﹣(AO﹣8)2,
解得AO=13cm.即圆弧半径为13米.
答:石拱桥拱的半径为13m.
阅读下面材料,有的答案要填入适当的内容,有的答案要用括号内单词的正确形式,但每个答案不多于3个单词。
Today,the ____(popular) of basketball has risen around the world,with many young people dreaming ____becming famous player.In China,you ____(see)people playing basketball now and then in parks,schools and even ____(factory).Basketball has not onlu become a pilular sport to play,but it has ____become a popular sport to watch.Although America's NBA games are ____(famous) in the world,the CBA games are becoming more popular in China.____number of foreign players,including Chinese players,in the NBA has increased.There ____also more and more foreign players in the CBA.Many young people look up to these basketball heroes and want to become like ____(they )These stars encourage young people____(work ) hard to achieve their dreams.
《水浒》“耗国因家木,刀兵点水工。纵横三十六,播乱在江东”,这首童谣唱的是____。
崔彦桐是我市潍州社区一位退休老人, 他十年如一日, 照顾社区里一位无儿无女的残疾人,为他打扫卫生,洗衣服,整理房间。 “是共产党员就要时刻想着人民群众” ,这是他常说的一句话。 “潍坊好.人”崔彦桐的言行向你传递的正能量有()①正确行使自己的权利, 履行不应履行的义务②践行社会主义核心价值观③坚守党全心全意为人民服务的宗旨④要让人生价值闪现着创造的光辉