一个圆台的母线长25厘米。
\u4e00\u4e2a\u5706\u53f0\u7684\u6bcd\u7ebf\u957f24cm,\u4e24\u5e95\u9762\u79ef\u4e3a4\u03c0cm2\uff0c25\u03c0cm2\u4e0a\u5e95 r=2 \u4e0b\u5e95r\uff1d5 \u6bcd\u7ebf\u957f\u4e3a24 \u5219\u9ad8\uff1d\uff0824^2-\uff085*2-2*2)^2\uff09^1/2=18
\u8bbe\u5706\u9525\u6bcd\u7ebf\u957fx \u5219\uff1a(x-24)/x)=2/5 \u5373 x\uff1d40 \u88c1\u5f97\u6b64\u5706\u53f0\u7684\u5706\u9525\u6bcd\u7ebf\u957f\u4e3a40
\u6839\u636e\u5706\u53f0\u7684\u6027\u8d28\u7684\uff1a
(1)\u5982\u56fe\uff0c\u8fc7\u5706\u53f0\u7684\u8f74\u4f5c\u622a\u9762\u4e3a\u7b49\u8170\u68af\u5f62ABCD\uff0c\u7531\u5df2\u77e5\u53ef\u5f97\u4e0a\u5e95\u534a\u5f84O1A\uff1d2 cm\uff0c
\u4e0b\u5e95\u534a\u5f84OB\uff1d5 cm\uff0c\u4e14\u8170\u957fAB\uff1d12 cm
. \u2234AM\uff1d \uff1d3(cm)\uff0c \u5373\u5706\u53f0\u7684\u9ad8\u4e3a3 cm.
(2)\u8bbe\u622a\u5f97\u6b64\u5706\u53f0\u7684\u5706\u9525\u7684\u6bcd\u7ebf\u957f\u4e3al\uff0c \u5219\u7531\u25b3SAO1\u223d\u25b3SBO\uff0c
\u2234l\uff1d20(cm)\uff0c
\u5373\u622a\u5f97\u6b64\u5706\u53f0\u7684\u5706\u9525\u7684\u6bcd\u7ebf\u957f\u4e3a20 cm.
\u6269\u5c55\u8d44\u6599\uff1a
\u6027\u8d28
\u5e73\u884c\u4e8e\u5e95\u9762\u7684\u622a\u9762\u662f\u5706\u3002
\u8fc7\u8f74\u7684\u622a\u9762\u662f\u7b49\u8170\u68af\u5f62\u3002
\u540c\u522b\u7684\u68f1\u53f0\u4e00\u6837\uff0c\u82e5\u5b83\u662f\u4e00\u4e2a\u5706\u9525\u4f53\u5728½\u5904\u622a\u65ad\uff0c\u5219\u4e0a\u5e95\u534a\u5f84\u4e5f\u5e94\u4e3a\u4e0b\u5e95\u76841/2\uff0c\u622a\u4e0b\u9762\u79ef\u662f\u6574\u4e2a\u5706\u9525\u9762\u79ef\u76841/7.\u8fc7\u5706\u53f0\u4fa7\u9762\u4e00\u70b9\u6709\u4e14\u53ea\u6709\u4e00\u6761\u6bcd\u7ebf\u3002
\u5982\u679c\u6cbf\u4e00\u4e2a\u76f4\u89d2\u68af\u5f62\u5782\u76f4\u4e8e\u5e95\u8fb9\u7684\u8170\u65cb\u8f6c\u4e00\u5468\uff0c\u5c06\u5f97\u5230\u4e00\u4e2a\u5706\u53f0\u3002
\u5706\u53f0\u4efb\u610f\u4e24\u6761\u6bcd\u7ebf\u5ef6\u957f\u540e\u4ea4\u4e8e\u4e00\u70b9\u3002
\u76f4\u89c2\u56fe\u5706\u53f0\u7684\u4e0a\u3001\u4e0b\u5e95\u9762\u90fd\u662f\u5706\uff0c\u5706\u7684\u76f4\u89c2\u56fe\uff0c\u4e00\u822c\u4e0d\u7528\u659c\u4e8c\u4fa7\u753b\u6cd5\uff0c\u800c\u7528\u6b63\u7b49\u6d4b\u753b\u6cd5\u3002\u5b83\u7684\u89c4\u5219\u662f\uff1a
(1)\u5728\u5df2\u77e5\u56fe\u5f62\u5706O\u4e2d\u53d6\u4e92\u76f8\u5782\u76f4\u7684\u8f74Ox,Oy\u3002\u753b\u76f4\u89c2\u56fe\u65f6\uff0c\u628a\u5b83\u4eec\u753b\u6210\u5bf9\u5e94\u7684\u8f74O'x',O'y',\u4f7f\u2220x'O'y'=120\u00b0(\u621660\u00b0)\uff0c\u5b83\u4eec\u786e\u5b9a\u7684\u5e73\u9762\u8868\u793a\u6c34\u5e73\u5e73\u9762\uff1b
(2)\u5df2\u77e5\u56fe\u5f62\u4e0a\u5e73\u884c\u4e8ex\u8f74\u6216y\u8f74\u7684\u7ebf\u6bb5\uff0c\u5728\u76f4\u89c2\u56fe\u4e2d\uff0c\u5206\u522b\u753b\u6210\u5e73\u884c\u4e8ex'\u8f74\u6216y'\u8f74\u7684\u7ebf\u6bb5\uff1b
(3)\u5e73\u884c\u4e8ex\u8f74\u6216y\u8f74\u7684\u7ebf\u6bb5\uff0c\u957f\u5ea6\u90fd\u4e0d\u53d8\u3002
\u53c2\u8003\u8d44\u6599\uff1a\u767e\u5ea6\u767e\u79d1\u2014\u2014\u5706\u53f0
绛旓細鐢诲欢闀跨嚎浜や笌涓鐐圭劧鍚庡仛鍨傜嚎寰楀埌鐨勮涓30掳涔熷氨鏄浘涓殑瑙扙AO涓30掳銆傚仛ED鐨勫瀭绾匡紒寰楀埌瑙扗EC=瑙扙A0=30掳 宸茬煡EC涓20cm锛屾牴鎹甤os30掳=ED/EC=ED/20= 鏇村彿3/2 ED=10鈭3 寰楀埌DC灏辩瓑浜10锛岀劧鍚嶧D=OE鎵浠ヤ笅搴曢潰鍗婂緞灏辩瓑浜10+15=25cm 搴曢潰鍗婂緞=蟺 r² =25²脳蟺=625蟺锛坈...
绛旓細鍦嗗彴鐨涓婅〃闈㈢殑鍗婂緞涓篴=12sin15掳cos45掳=2.2cm锛涘渾鍙扮殑涓嬭〃闈㈢殑鍗婂緞涓篵=12cos15掳sin45掳=8.2cm锛涘渾鍙扮殑浣撶Н涓猴細V=蟺*tan60掳*(b^3-a^3)/3=980.8cm^3銆
绛旓細涓嬪簳闈㈢Н=25蟺,AB=12鈭磖=鈭4蟺/蟺=2,R=鈭25蟺/蟺=5鈭礝1A鈭2B鈭碢A:PB=O1A:O2B=r:R=2:5PB=PA+AB=PA+12瑙ｅ緱 鎴幓鍦嗛敟鐨勬瘝绾块暱PA=8cm鏍规嵁鍕捐偂瀹氱悊(褰撶劧浣犱篃鍙互鐢ㄤ笂闈㈡瘮渚嬬殑鏂规硶)鍦嗗彴鐨楂極1O2=鈭欰B^2-(R-r)^2=3鈭15cm涔熷彲鑳介氳繃璁＄畻PO1鍜孭O2鐨勬柟娉曟潵璁＄畻O1O2 ...
绛旓細鏍规嵁鍦嗗彴鐨鎬ц川鐨勶細(1)濡傚浘锛岃繃鍦嗗彴鐨勮酱浣滄埅闈负绛夎叞姊舰ABCD锛岀敱宸茬煡鍙緱涓婂簳鍗婂緞O1A锛2 cm锛屼笅搴曞崐寰凮B锛5 cm锛屼笖鑵伴暱AB锛12 cm . 鈭碅M锛 锛3(cm)锛 鍗冲渾鍙扮殑楂樹负3 cm.(2)璁炬埅寰楁鍦嗗彴鐨勫渾閿鐨勬瘝绾块暱涓簂锛 鍒欑敱鈻砈AO1鈭解柍SBO锛屸埓l锛20(cm)锛屽嵆鎴緱姝ゅ渾鍙扮殑鍦嗛敟鐨勬瘝绾块暱涓20 cm...
绛旓細鍏充簬鍦嗗彴姣嶇嚎闀璁＄畻鍏紡锛鍦嗗彴姣嶇嚎杩欎釜寰堝浜鸿繕涓嶇煡閬擄紝浠婂ぉ鏉ヤ负澶у瑙ｇ瓟浠ヤ笂鐨勯棶棰橈紝鐜板湪璁╂垜浠竴璧锋潵鐪嬬湅鍚э紒1銆佷互鐩磋姊舰鍨傜洿浜庡簳杈圭殑鑵版墍鍦ㄧ洿绾夸负鏃嬭浆杞达紝鍏朵綑鍚勮竟鏃嬭浆鑰屽舰鎴愮殑鏇查潰鎵鍥存垚鐨勫嚑浣曚綋鍙仛鍦嗗彴锛庢棆杞酱鍙仛鍦嗗彴鐨杞达紟鐩磋姊舰涓娿佷笅搴曟棆杞墍鎴愮殑鍦嗛潰绉颁负鍦嗗彴鐨勪笂銆佷笅搴曢潰锛屽彟涓鑵版棆杞墍...
绛旓細涓婂簳闈负40cm 涓嬪簳闈负30cm锛屾槸鐩村緞鍚楋紵S=S渚+S搴=1/2锛40蟺+30蟺锛50+15*15*蟺=1750蟺+225蟺=1975蟺 娉ㄦ剰S渚т笌姊舰闈㈢Н璁＄畻鏂规硶鍚
绛旓細鍦嗗彴鐨渚ч潰绉=锛圧 + r锛壝椣脳L姣嶇嚎 鍋囪鍦嗗彴鐨勪笂搴曢潰鐩村緞涓3D,鍒欎笅搴曢潰鐩村緞涓4D (3D)^2/2 + (4D)^2/2 =L^2 L=5D/鏍瑰彿2 140=锛3D/2 + 4D/2锛壝椣脳5D/鏍瑰彿2 D=8鏍瑰彿2 鍒橪=10脳鈭(4&2) ---鈭(4&2)2寮4娆℃柟 ...
绛旓細鍦嗗彴鐨楂 = h, 涓嬪簳鍗婂緞 = r r - 15 = 20sin30搴=10 r=25 h = 20 cos30搴 = 17.32cm 鍦嗗彴鐨勯珮17.32cm 涓嬪簳鐨勯潰绉 = pai(25^2)= 1963.50 cm^2
绛旓細鐭ラ亾涓や釜搴曢潰绉氨鐭ラ亾涓ゅ簳闈㈠崐寰勫垎鍒负2鍜5锛屼綔鍦嗗彴鐨姝ｈ鍥惧嵆涓虹瓑瑕佹褰紝鍐嶅湪涓婂簳涓杈硅浣滈珮锛屽緢娓呮鏄嬀鑲″畾鐞嗭紝搴旇楂樹负3鍙堟牴鍙15
绛旓細鍏跺疄杩欎釜璁茬殑閮芥槸搴熻瘽锛屽彧鏈涓涓鏄潯浠跺氨鏄晶闈㈢Н=涓婁笅搴曠殑闈㈢Н锛屽叾浠栭兘鏄畾寰 鏈夐鎰忓緱锛氫晶闈㈢Н=1/2 锛堜笂涓嬪簳鍛ㄩ暱涔嬪拰锛*姣嶇嚎闀 =蟺 锛圧²+r²)鍗虫瘝绾块暱 = 蟺锛圧²+r²) / 蟺(R+r) = (R²+r²) / (R+r)浠旂粏涓鐐圭殑鐪嬩笅闈㈢殑璇存槑 璁撅細S1涓簉鍦...
