Èçͼ£¬ÒÑÖªÖ±½ÇÌÝÐÎABCDÖУ¬AD¡ÎBC£¬AB¡ÍBC £¬AD£½2cm£¬AB£½8cm£¬CD£½10cm£®
(1)ÇóÌÝÐÎABCDµÄÖܳ¤£»
(2)¶¯µãP´ÓµãB³ö·¢£¬ÒÔ1cm/sµÄËÙ¶ÈÑØB¡úA¡úD¡úC·½ÏòÏòµãCÔ˶¯£»¶¯µãQ´ÓµãC³ö·¢£¬ÒÔ1cm/sµÄËÙ¶ÈÑØC¡úD¡úA·½ÏòÏòµãAÔ˶¯£»¹ýµãQ×÷QF¡ÍBCÓÚµãF£®ÈôP¡¢QÁ½µãͬʱ³ö·¢£¬µ±ÆäÖÐÒ»µãµ½´ïÖÕµãʱÕû¸öÔ˶¯ËæÖ®½áÊø£¬ÉèÔ˶¯Ê±¼äΪtÃ룮ÎÊ£º
ÔÚÔ˶¯¹ý³ÌÖУ¬ÊÇ·ñ´æÔÚÕâÑùµÄt£¬Ê¹µÃÒÔP¡¢D¡¢QΪ¶¥µãµÄÈý½ÇÐÎÇ¡ºÃÊÇÒÔDQΪһÑüµÄµÈÑüÈý½ÇÐΣ¿Èô´æÔÚ£¬ÇëÇó³öËùÓзûºÏÌõ¼þµÄtµÄÖµ£»Èô²»´æÔÚ£¬Çë˵Ã÷ÀíÓÉ£®
(1) 28cm(2) µ±t=»ò8¡Üt£¼10»ò10£¼t¡Ü12ʱ£¬ÒÔP¡¢D¡¢QΪ¶¥µãµÄÈý½ÇÐÎÇ¡ºÃÊÇÒÔDQΪһÑüµÄµÈÑüÈý½ÇÐνâÎö:
½â£º£¨1£©¹ýµãD×÷DE¡ÍBCÓÚµãE
¡ßËıßÐÎABCDÊÇÖ±½ÇÌÝÐÎ
¡àËıßÐÎABEDÊǾØÐÎ
¡àAD=BE=2£¬AB=DE=8
ÔÚRt¡÷DECÖУ¬CE==="6"
¡àÌÝÐÎABCDµÄÖܳ¤= AB+BC+CD+DA=8+8+10+2=28cm.
¡­¡­¡­3·Ö
£¨2£© ¢Ù µ±0¡Üt¡Ü8ʱ£¬¹ýµãQ×÷QG¡ÍABÓÚµãG
ÔòAP=8£­t£¬DQ=10£­t£¬AD=2£¬
¡ßRt¡÷CQF¡×Rt¡÷CDE
¡àCF=£¬QF=£¬¡àPG==£¬QG=8£­
=£¨8£­t£©2+22=t2£­16t+68£¬
PQ2=QG2+PG2=£¨8£­£©2+£¨£©2= 
ÈôDQ=PD£¬Ôò£¨10£­t£©2= t2£­16t+68£¬½âµÃ£ºt=8£»¡­¡­¡­¡­¡­¡­¡­5·Ö
ÈôDQ=PQ£¬Ôò£¨10£­t£©2=£¬       
½âµÃ£ºt1= £¬t2=£¾8£¨ÉáÈ¥£©£¬´Ëʱt=£»¡­¡­¡­6·Ö
¢Úµ±8£¼t£¼10ʱ£¬PD=DQ=10£­t£¬                
¡à´ËʱÒÔDQΪһÑüµÄµÈÑü¡÷DPQºã³ÉÁ¢£» ¡­¡­¡­¡­¡­¡­¡­¡­7·Ö
¢Ûµ±t=10ʱ£¬µãP¡¢D¡¢QÈýµãÖغϣ¬ÎÞ·¨¹¹³ÉÈý½ÇÐΣ»¡­¡­¡­¡­¡­¡­¡­¡­¡­8·Ö
¢Üµ±10£¼t¡Ü12ʱ£¬PD="DQ=" t£­10£¬
¡à´ËʱÒÔDQΪһÑüµÄµÈÑü¡÷DPQºã³ÉÁ¢£»     ¡­¡­¡­¡­¡­¡­¡­¡­¡­9·Ö
×ÛÉÏËùÊö£¬µ±t=»ò8¡Üt£¼10»ò10£¼t¡Ü12ʱ£¬ÒÔP¡¢D¡¢QΪ¶¥µãµÄÈý½ÇÐÎÇ¡ºÃÊÇÒÔDQΪһÑüµÄµÈÑüÈý½ÇÐÎ.                ¡­¡­¡­¡­¡­¡­¡­¡­¡­10·Ö
£¨1£©¹ýµãD×÷DE¡ÍBCÓÚµãE£¬È»ºóÇó³öAD=BE=2£¬AB=DE=8£¬ÔÚRt¡÷DECÖУ¬¸ù¾ÝCE= Çó³öCE£¬¼´¿ÉÇó³öBCµÄ³¤£¬´Ó¶øÇóµÃÌÝÐÎABCDµÄÖܳ¤
£¨2£©£¨i£©µ±0¡Üt¡Ü8ʱ£¬¹ýµãQ×÷QG¡ÍABÓÚµãG£¬¹ýµãQ×÷QF¡ÍCBÓÚµãF£¬¸ù¾Ý¡÷CQF¡×¡÷CDEµÃ³ö£¬ËùÒÔCF= £¬QF= £¬ËùÒÔPG=t= £¬QG=8-£¬È»ºó·Ö±ðÓÃt±íʾ³öPD2=t2-16t+68£¬PQ2=+64£¬ÈôDQ=PD£¬Ôò£¨10-t£©2=t2-16t+68£¬ÈôDQ=PQ£¬Ôò£¨10-t£©2=+64£¬×îºó½â·½³Ì¼´¿É£»
£¨ii£©µ±8£¼t£¼10ʱ£¬PD=DQ=10-t£¬´ËʱÒÔDQΪһÑüµÄµÈÑü¡÷DPQºã³ÉÁ¢£»¶øµ±t=10ʱ£¬µãP¡¢D¡¢QÈýµãÖغϣ¬ÎÞ·¨¹¹³ÉÈý½ÇÐΣ¬µ±10£¼t¡Ü12ʱ£¬PD="DQ=" t£­10£¬´ËʱÒÔDQΪһÑüµÄµÈÑü¡÷DPQºã³ÉÁ¢£¬´Ó¶øµÃ³ö×îºó´ð°¸£»
Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

¾«Ó¢¼Ò½ÌÍøÈçͼ£¬ÒÑÖªÖ±½ÇÌÝÐÎABCDÖУ¬AD¡ÎBC¡ÎEF£¬¡ÏA=90¡ã£¬BC=DC=4£¬AC¡¢BD½»ÓÚE£¬ÇÒEF=ED£®
£¨1£©ÇóÖ¤£º¡÷DBCΪµÈ±ßÈý½ÇÐΣ®
£¨2£©ÈôMΪADµÄÖе㣬Çó¹ýM¡¢E¡¢CµÄÅ×ÎïÏߵĽâÎöʽ£®
£¨3£©Åж¨¡÷BCDµÄÍâÐÄÊÇ·ñÔÚ¸ÃÅ×ÎïÏßÉÏ£¨ËµÃ÷ÀíÓÉ£©

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

21¡¢µ±ÎÒÃÇÓöµ½ÌÝÐÎÎÊÌâʱ£¬ÎÒÃdz£Ó÷ָîµÄ·½·¨£¬½«Æäת»¯³ÉÎÒÃÇÊìϤµÄͼÐÎÀ´½â¾ö£º
£¨1£©°´ÒªÇó¶ÔÏÂÁÐÌÝÐηָ·Ö¸îÏßÓÃÐéÏߣ©
¢Ù·Ö¸î³ÉÒ»¸öƽÐÐËıßÐκÍÒ»¸öÈý½ÇÐΣ»  ¢Ú·Ö¸î³ÉÒ»¸ö³¤·½ÐκÍÁ½¸öÖ±½ÇÈý½ÇÐΣ»

£¨2£©Èçͼ£¬ÒÑÖªÖ±½ÇÌÝÐÎABCDÖУ¬AD¡ÎBC£¬¡ÏB=90¡ã£¬AB=4cm£¬BC=8cm£¬¡ÏC=45¡ã£¬ÇëÄãÓÃÊʵ±µÄ·½·¨¶ÔÌÝÐηָÀûÓ÷ָîºóµÄͼÐÎÇóADµÄ³¤£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

Èçͼ£¬ÒÑÖªÖ±½ÇÌÝÐεÄÒ»Ìõ¶Ô½ÇÏß°ÑÌÝÐηÖΪһ¸öÖ±½ÇÈý½ÇÐκÍÒ»¸ö±ß³¤Îª8cmµÄµÈ±ßÈý½ÇÐΣ¬ÔòÌÝÐεÄÖÐλÏß³¤Îª £¨¡¡¡¡£©

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

Èçͼ£¬ÒÑÖªÖ±½ÇÌÝÐÎABCDÖУ¬AD¡ÎBC£¨AD£¼BC£©£¬¡ÏB=90¡ã£¬AB=AD+BC£®µãEÊÇCDµÄÖе㣬µãFÊÇABÉϵĵ㣬¡ÏADF=45¡ã£¬FE=a£¬ÌÝÐÎABCDµÄÃæ»ýΪm£®
£¨1£©ÇóÖ¤£ºBF=BC£»
£¨2£©Çó¡÷DEFµÄÃæ»ý£¨Óú¬a¡¢mµÄ´úÊýʽ±íʾ£©

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º³õÖÐÊýѧ À´Ô´£º ÌâÐÍ£º

Èçͼ£¬ÒÑÖªÖ±½ÇÌÝÐÎABCDÖУ¬AD¡ÎBC£¬¡ÏB=90¡ã£¬¡ÏC=60¡ã£¬BC=12cm£¬DC=16cm£¬¶¯µãPÑØA¡úD¡úCÏß·ÒÔ2cm/ÃëµÄËÙ¶ÈÏòCÔ˶¯£¬¶¯µãQÑØB¡úCÏß·ÒÔ1cm/ÃëµÄËÙ¶ÈÏòCÔ˶¯£®P¡¢QÁ½µã·Ö±ð´ÓA¡¢Bͬʱ³ö·¢£¬µ±ÆäÖÐÒ»µãµ½´ïCµãʱ£¬ÁíÒ»µãÒ²Ëæֹ֮ͣ£®ÉèÔ˶¯Ê±¼äΪtÃ룬¡÷PQBµÄÃæ»ýΪy cm2£®
£¨1£©ÇóADµÄ³¤¼°tµÄÈ¡Öµ·¶Î§£»
£¨2£©Çóy¹ØÓÚtµÄº¯Êý¹Øϵʽ£»
£¨3£©ÊÇ·ñ´æÔÚÕâÑùµÄt£¬Ê¹µÃ¡÷PQBµÄÃæ»ýΪ
9
3
2
£®

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸