Chi/dNq MAT NON, MAT TRU, MAT CAU Phan G\d\ THliu CHLfdNG I CAU TAO CHUONG § Khai niem vd mat trdn xoay §2 Mat ciu On tap chuang II Muc dich cua chuong • Chuang II nhim cung cap cho hgc sinh nhiing kie'n thiic co ban vd khai nidm cac khdi trdn xoay khdng gian ma chii ye'u la mat ndn, mat tru va mat ciu Mat ndn trdn xoay : Day, dudng sinh va dudng trdn day Dien tfch xung quanh va dien tich toan phin ciia mat ndn Thd tfch ciia khdi ndn trdn xoay • Mat tru trdn xoay la gi ? Didn tfch xung quanh va dien tfch toan phan eua mat tru The tfch ciia khdi tru trdn xoay • Mat cau la gi ? Didn tfch ciia mat ciu The tfch ciia khdi cau 104 I I - MUC TIEU Kien thufc Nim dugc toan bd kien thiic ca ban chuong da neu tren - Hidu eac khai niem cac mat trdn xoay: Mat ndn, mat tru va mat cau Nim dugc eac cdng thitc tfnh didn tfch, thd tfch ciia cac khdi trdn xoay KI nang TinK dugc didn tfch xung quanh, didn tfch toan phan ciia cac hinh trdn xoay Tinh dugc thd tfch ciia hinh tru, hinh ndn Thai Hgc xong chuang hgc sinh se lien he dugc vdi nhidu va'n dd thuc te sinh ddng, lien he duge vdi nhung vin dd hinh hgc da hgc d Idp dudi, md mdt each nhin mdi vd hinh hgc Tii dd, cac em cd thd tu minh sang tao nhiing bai toan hoac nhirng dang toan mdi Kit ludn: Khi hgc xong chuang hgc sinh cin lam tdt cac bai tap sach giao khda va lam dugc cae bai kidm tra chuang 105 Phan 2, ckc BAI SOAN §1 Khai niem ve mat tron xoay (tiet 1, 2, 3, 4, 5) MUC Tl!U Kien thufc HS nim dugc: Khai niem chung vd mat trdn xoay Hidu va van dung tfnh the tfch binh tru va binh ndn Dien tfch xung quanh va toan phin ciia mat tru va mat ndn KT nang • Ve thao cac mat tru va mat ndn • Tinh nhanh va chfnh xac didn tfch va the tfch hinh tru va hinh ndn • Phan chia mat tru va mat ndn bing mat phang Thai • Lien he dugc vdi nhidu van dd thue te khdng gian • Cd nhidu sang tao hinh hgc • Hiing thii hgc tap, tfch cue phat huy tfnh ddc lap hgc tap n CHUAN DI CUA GV VA HS Chuan bi cua GV: • Hinh ve 2.1 de'n 2.12 • Thudc ke, phin mau, 106 Chuan bi ciia HS : Dgc bai trudc d nha, cd thd lien he cac phep bie'n hinh da hgc d Idp dudi PHAN DHOI TH6I LUONG Bai dugc chia tiet: Tiet 1: Tii dau de'n he't phan Tie't 2: Tie'p theo de'n he't muc phin II Tidt 3: Tie'p theo de'n he't phin II Tie't 4: Tie'p theo de'n bet muc phin III Tie't 3: Tidp theo den bet phin III IV TlfN TDiNH DAY HOC n DAT VAN D€ Cau hdi Nhic lai khai nidm hinh ndn va hinh tru da hgc d cap Cau hdi Ndu mdt sd hinh ndn va hinh tru thuc te B Biil MOI HOATDQNGl I sir TAG THANH MAT TRON XOAY GV neu cau hoi : HI Lg hoa thdng thudng ed phai mat trdn xoay hay khdng? H2 Chie'c ndn Hue la mat trdn xoay? 107 • GV sir dung hinh 2.1 SGK va dat va'n dd: H3 Hay dgc ten cac hinh d hinh 2.1 H4 Em hinh dung dugc each lam lg hoa H5 Trong cac mat trdn xoay, cd mat nao chic chin la mat phing? H6 Trong hinh 2.2, cit qua A mdt mat phing bat ki ta cd dugc dudng ^ hay khdng? H7 Ndu mdt sd hinh anh thuc te vd hinh tru va hinh ndn HOATDQNG II MAT NON TRON XOAY Dinh nghla • GV eho HS tu phat bidu dinh nghia cua minh va sau dd kdt luan: Trong mat phdng (P) cho hai dudng thdng d vd A cdt tgi tgo thdnh gdc nhgn /? Khi quay mat phdng xung quanh A thi dudng thdng d sinh mdt mat trdn xoay vd dugc ggi Id mat ndn trdn xoay dinh ngUdi ta thudng ggi tat la mat ndn Dudng thang A ggi Id true, dudng thdng d ggi Id dudng sinh, gdc 2/3 ggi Id gdc d dinh cua mat ndn dd Six dung hinh 2.3 va dat eac cau hdi: H8 Phai chang mat ndn cd gidi ban bdi hai mat phang song song vdi H9 Gdc giiia dudng sinh va true ludn ludn khdng ddi HIO Cd mdt phep ddi xitng tam O bid'n mdi diem ciia mat ndn mdi didm ciia mat ndn Hinh ndn trdn xoay va khdi ndn tron xoay • Sit dung hinh 2.4 va md ta: 108 • GV neu dinh nghia ; Cho tam gidc vudng lOM Khi quay nd xung quanh mgt cgnh gdc vudng 01 ta dugc mgt tgo thdnh mdt hinh dugc ggi Id hinh ndn trdn xoay Ta thudng ggi tdt Id hinh ndn • GV cd thd dat cau hdi: HI Hai tam giac lOM va lOM' ed bing khdng? HI2 Hay neu tap hgp didm ciia M • GV ndu tiep khai niem: O ggi la dinh cua hinh ndn IM ggi la dudng sinh ciia hinh ndn 10 ggi Id dudng cao ciia hinh ndn Tap hgp diemM la dudng trdn tdm I bdn kinh IM ggi Id ddy ciia hinh ndn Phdn hinh ndn bd di mat ddy ggi Id mat xung quanh cua hinh ndn H13.10 vudng gdc vdi day Diing hay sai H14 Gdc tao bdi dudng sinh va dudng cao bing bao nhieu Ian gdc d dinh • GV ndu dinh nghia khdi ndn trdn xoay: Khdi ndn trdn xoay Id phdn khdng gian gidi hgn bdi hinh ndn trdn xoay vd cd hinh ndn 109 N la diem ne'u N thudc khd'i ndn N Id diem ngodi niu N khdng thugc khd'i ndn H15 Hay neu khai niem dinh, day, dudng sinh, dudng cao ciia khdi ndn Dien tich xung quanh cua hinh ndn trdn xoay HI6 Hay ve mdt hinh chdp cd tat ca eac dinh cua day hinh chdp la da giac ndi tie'p dudng trdn day cia hinh ndn Dinh cua hinh chdp trimg vdi dinh ciia hinh ndn H17 Tam ciia da giac va tam ciia dudng trdn day ludn triing diing hay sai? • GV ndu dinh nghla : Dien tich xung quanh cua hinh ndn trdn xoay la gidi hgn cua dien tich xung quanh cua hinh chdp deu ndi tiep hinh ndn dd sd cgnh ddy tdng len vd hgn HI8 Didn tfch xung quanh ciia hinh chdp ddu ndi tie'p hinh ndn Idn ban hay nho ban didn tfch xung quanh cua hinh ndn? H19 Khi nao dien tfch hinh chdp va hinh ndn nhu tren triing nhau? H20 Nhic lai cdng thiic tfnh dien tfch xung quanh cua hinh ndn • GV nhic lai cdng thiie : S = — pq dd q la khoang each tit O de'n mdt canh p la chu vi day H21 Khi n ^^co thi p din de'n sd nao ? • GV neu dinh If: Dien tich xung quanh cua hinh ndn bdng nda chu vi ddy nhdn vdi ddi dudng sinh S^q=7ir/ no • GV ndu tidp dinh nghla: Tdng cua dien tich xung quanh vd dien tich ddy ggi Id dien tich todn phdn cua hinh ndn The tich cua hinh ndn trdn xoay • GV neu dinh nghia : The tich cua hinh ndn trdn.xoay Id gidi hgn cua the tich cUa hinh chdp diu ndi tie'p hinh ndn dd sd cgnh ddy tdng len vd hgn H22 Ndu cdng thiic tfnh the tfch hinh chdp GV nhic lai V f = - B h • ^ H23 Khi sd eanh cua hinh chdp dan tdi cx) thi didn tfch day din de'n sd nao? • GV ndu cdng thiic : 1 V„ - - B h ^ - T t r ^ h Vi du •GV cho HS tdm tit vf du: 111 Cau a Hoat ddng cua GV Cdu hdi Hoat ddng cua HS Ggi y trd ldi cdu hdi I Hay chi dudng sinh cua hinh Dudng smh la OM ndn Ggi y trd ldi cdu hdi Cdu hdi IM , „,, Tfnh dai dudng sinh - OM = = 2a sin 30° Cdu hdi Tinh chu vi day Ggi y trd ldi cdu hdi p =2 Ttr = 2Tr.a Cdu hdi Tinh dien tfch xung quanh cua Ggi y trd ldi cdu hdi , Sxq = nr\ = 2na^ hinh ndn caub Hoat ddng ciia GV Cdu hdi Hoat ddng ciia HS Ggi y trd ldi cdu hdi I Tfnh dien tfch day Cdu hdi S = na^ Ggi y trd ldi cdu hdi Tfnh dudng cao Cdu hdi OI = aV3 Ggi y trd ldi cdu hdi TinhV V- Thuc hidn ^ phiit S 112 ^^^^'^ Hoat ddng cua HS Hoat ddng ciia GV Cdu hdi Ggi y trd ldi cdu hdi Tfnh chu vi niia dudng trdn ldn Cdu hdi Niia chu vi ciia dudng trdn ldn la chu vi dudng trdn nhd va bing 27IT So sanh chu vi ciia dudng trdn Ggi y trd ldi cdu hdi day va niia chu vi dudng trdn ldn Bang Cdu hdi Ggi y trd ldi cdu hdi Tfnh r 13 Ta cd TTR = 270- Tit dd r = — HOAT DONG IIL MAT TRU TRON XOAY Djnh nghla • GV sii dung hinh 2.8 va dat cac cau hdi: 113 (a) a ; (b) 2a (c) ayfs ; (d)aV2 Trd ldi (b) Cdu Cho hinh chdp SABCD, day ABCD la hinh thang vudng tai A, SA J.(ABCD), SA = a, AB = 2a, AD = DC = a Thd tfch khdi chdp la (a) (b) (c) (d) Ca ba cau trdn ddu sai Trd ldi (a) Cdu Cho hinh chdp SABCD, day ABCD la hinh thang vudng tai A, SA ±(ABCD), SA = a, AB = 2a, AD = DC = a The tfch khdi chdp S.ABC la (a) -f (d) Ca ba cau trdn ddu sai Trd ldi (b) Cdu Cho hinh chdp SABCD, day ABCD la hinh thang vudng tai A, SA ±(ABCD), SA = a, AB = 2a, AD = DC = a Khoang each giiia SA va BC la: 148 (a) a ; (b)2a 2a Ve (c) aV2 ; Trdldi (d) Cdu 10 Cho hinh chop SABCD, day ABCD la hinh thang vudng tai A, SA l(ABCD), SA = a, AB = 2a, AD = DC = a Dien tfch tam giac SBC la: S (a) a^; (c) a^yfl ; (d)- • ^ z Trd ldi (d) Cdu 11 Cho hinh chdp SABCD, day ABCD la hinh vudng canh a, SA l(ABCD), SA = a Khoang each giiia AB va SD la: 149 (a) a; (c) aV2 ; Trd ldi (d) Cdu 12 Cho hinh chdp SABCD, day ABCD la hinh vudng tam O canh a, SA l(ABCD), SA = a Khi dd SO bing (a) a; (c) aV2 ; Trd ldi (d) 150 Cdu 13 Cho hinh chdp ndi tie'p mdt hinh ndn (a) Hai hinh chdp va hinh ndn cd dudng cao trung nhau; (b) Thd tfch hinh chdp va thd tfch hinh ndn bing (c) Thd tfch hinh chop ldn hon thd tfch hinh ndn (d) Ca ba y trdn ddu diing Trd ldi (a) Cdu 14 Cho hinh chdp luc giac ddu canh day la 2v3 ndi tie'p mdt hinh ndn cd dudng cao la Dudng cao ke tit S cua mdi mat ben eiia hinh chdp la : (a)2VlO; (c) VlO (b)VIo (d)10 Trdldi (b) 151 Cdu 15 Cho hinh chdp luc giac ddu eanh day la 2\f3 ndi tid'p mdt hinh ndn cd dudng cao la Didn tfch xung quanh ciia hinh chdp la : (a)6V30; (b) VSO (c)4V30; Trd ldi (a) (d)5V30 Cdu 16 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tidp mdt hinh ndn cd dudng cao la Ban kfnh dudng trdn day la: (a) 2V3; , - 2V3 (0—; Trd ldi (a) 152 (b) 2V6 (d)yf3 Cdu 17 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tidp mdt hinh ndn cd dudng cao la S Dudng sinh la: (a) 2V3; (b) 2V6 , , 2V3 (d) V3 (0—; Trdldi (b) Cdu 18 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tiep mdt hinh ndn cd dudng cao la S Didn tfch xung quanh ciia hinh ndn la (a) 127tV2; (b) 24TtV2 153 (c) 671V2 ; (d) 487TV2 Trdldi (d) Cdu 11 Cho hinh chop luc giac ddu canh day la 2V3 ndi tie'p mdt hinh ndn cd dudng cao la Dien tfch toan phin cua hinh ndn la: (a) I271V2 + 1271; (b) 24TiV2 + 127t (c) 6TtV2 + 12Tt; (d) 487rV2 + 127i Trdldi (d) Cdu 19 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tiep mdt hinh ndn cd dudng cao la 154 The tfch cua hinh ndn la: (a) 1271; (b)67t (c) 871; (d) 1071 Trd ldi (a) Cdu 20 Cho hinh lang tru luc giac ddu canh day la 2V3 ndi tidp mdt hinh tru cd dudng cao la Didn tfch xung quanh ciia hinh lang tru la la: (a)36V3; (b) 16V3 (c)46V3; (d)26V3 Trdldi (a) Cdu 21 Cho hinh lang tru luc giac ddu canh day la 2V3 ndi tie'p mdt hinh tru cd dudng cao la 155 B' A' -> p D' E Dudng sinh ciia hinh tru la : (a)2V3; (b)3V3 (c) ; (d) Trd ldi (c) Cdu 22 Cho hinh lang tru luc giac ddu canh day la 2V3 ndi tidp mdt hinh tru cd dudng cao la B "^ C B' ^•~~y F D' E' 156 Ban kfnh day eua hinh tru la : (a)r = 2V3; (b)r = 3V3 (c)r = ; (d)r = Trdldi (a) Cdu 23 Cho hinh lang tru Itic giac ddu canh day la 2V3 ndi tie'p mdt hinh tru cd dudng cao la A ^ _ _ _ ^ , _ _ C Didn tfch xung quanh ciia hinh tru la (a)127tV3; (b) 147tV3 (c) 1271; (d) 1471 Trdldi (a) Cdu 24 Cho hinh lang tru luc giac ddu canh day la 2\G ndi tiep mdt hinh tru cd dudng cao la 157 Didn tfch toan phin ciia hinh tru la (a) iTiS ; (b)207tV3 (c) 127C; (d) 1471 Trdldi (b) 158 MUC LUC Ldi ndi ddu C/iwtmg/-KHOI DA Phdnl DI£N GIOI THifiU CHI/ONG 5 F/idVi - CAC BAI SOAN §1 Khai niem vi khoi da dien §2 Khoi da dien loi ua khdi da dien deu 24 §3 Khai niem the tich cua khoi da dien 41 On tap chuang 64 Cftu-ong - M A T NON, MAT TRU, MAT CAU 104 P/ia/i i - GIOI THifiU CHUONG 104 PMn - CAC BAI SOAN 106 §1 Khai niem ve mdt tron xoa\; 106 Mgt so cdu hoi on tap hgc ki 143 159 THIET KE BAI GIANG HINH HOC 12 TAP MOT TRAN VINH Chiu trdch nhiem xudt bdn NGUYEN KHAC OANH Bien tap ngi dung : PHAM QUOC TUAN Vebia: THANH HUYEN Trinh bdy : QUYNH TRANG sua bdn in : PHAM QUOC TUiW In 2.000 eudn khd x cm Tai Cong tyTNHH in Ha Anh Giay phep xuat ban sd: 127 - 2008/CXB/100 TK - 05/HN In xong va nop luu chidu nam 2008 Sach lien ket vdi Thi^lMBGBnh hocl2Tl Cong ty CO phan In va Phat hanh sach Vi?t Nam h INPHAVI Phat hanh tai Cong ty cd phan In va Phat hanh sach Viet Nam Dja chi : 78 - Dong Cac - Ddng Da - Ha Npi DT : (04) 5.11 5921 - Fax : (04) 5.11 5921 y - 202596) 22.000 D Gia: 22.000d [...]... day la 2> /3 ndi tidp mat hinh ndn cd dudng cao la 3 126 Didn tfch toan phin ciia hinh ndn la: (a) I2T1V2 + 127 1; (b) 24 TIV2 + 127 I (c) 6TiV2 + 127 r; (d) 48TI^+12TI Trdldi (d) Cdu 12 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tie] tiep mdt hinh ndn cd dudng cag la 3 Thd tfch ciia hinh ndn la: (a) 127 1; (b) 671 (c) 871; (d) IOTI Trdldi (a) Cdu 13 Cho hinh lang tru luc giac ddu eanh day la 2V3 ndi... trdn day la: (a) 2yf3; (b) 2V6 , 2V3 (0—; (d) V3 Trdldi (a) Cdu 9 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tie'p mdt hinh ndn cd dudng cao la 3 125 Dudng sinh la: (a)2V3; (b) 2V6 ,- 2V3 (d) V3 Trdldi (b) Cdu 10 Cho hinh chdp luc giac ddu canh day la 2> /3 ndi tiep mdt hinh ndn cd dudng cao la 3 Didn tfch xung quanh cua hinh ndn la (a) llnyfl; (b) 24 TIV2 (c) 6T1V2 ; (d) 48TI^ /2 Trdldi (d) Cdu 11... 2V3; (b)r = 3V3 (c) r = 3 ; (d) r = 6 Trd ldi (a) Cdu 16 Cho hinh lang tru luc giac ddu canb day la 2V3 ndi tie'p mdt hinh tru cd dudng cao la 3 A C 129 Dien tich xung quanh cua hinh tru la (a ) 127 tV3; (b) (c) 127 1; (d) 1471 HTIVS Trd ldi (a) Cdu 17 Cho hinh lang tru luc giac ddu canh day la 2V3 ndi tiep mgt hinh tru co dudng cao la 3 A B = H ^' , ^- C E' Dien tich toan phan ciia hinh tru la : (a ) 127 tV3;... hdi I Tinh didn tfch xung quanh ciia hinh tru Cdu hdi 2 Imh dial tfch toan phin eiia hinh tru S„- = 2TirI - 2Tir.rv3 = 2v3Tir Aq Ggi y trd ldi cdu hdi 2 S , p = S , q + 2 S d = 2 ( l + V3)Tir2 caub Hoat ddng ciia GV Cdu hdi I Hoat ddng cua HS Ggi y trd ldi cdu hdi I Nhic lai cdng thiic tfnh thd tfch V = Ttr^h hinh tru Ggi y trd ldi cdu hdi 2 Cdu hdi 2 TfnhV V = Trr^h = Ttr^rV3=Tir^V3 137 cauc Hoat ddng... y trd ldi cdu hdi I V = - Tir^h 3 133 Cdu hdi 2 Ggi y trd ldi cdu hdi 2 TinhV V= -n .25 ^ .20 3 cau c Hoat ddng cua HS Hoat ddng ciia GV Ggi y trd ldi cdu hdi 1 Cdu hdi 1 OH = 12 em Tfnh OH Ggi y trd ldi cdu hdi 2 Cdu hdi 2 ^ ^ TfnhOI 1 OH^ 1 , 1 h^ lO^ Tif dd ta cd IO = 15em Ggi y trd ldi cdu hdi 3 Cdu hdi 3 Dua vao tam giac vudng SOI ta cd Tinhs SI SI = 25 em Ggi y trd ldi cdu hdi 4 Cdu hdi 4 Tfnh dien... y trd ldi cdu hdi 1 Chi ra dudng cao h Cdu hdi 2 Cbl ra ban kfnh day Cdu hdi 3 Tam giac SOA cd dac didm gi ? h = SO = 20 cm Ggi y trd ldi cdu hdi 2 r = OA - OB = 25 cm Ggi y trd ldi cdu hdi 3 Tam giac SOA la tam giac vudng tai O Tir dd ta cd dudng sinh 1 = Vl 025 Cdu hdi 4 Tfnh dien tfch xung quanh ciia hinh ndn Ggi y trd ldi cdu hdi 4 S,„ =27 irl= 7T .25 .V1 025 Aq caub Hoat ddng cua GV Cdu hdi 1 Nhic lai... tie'p mdt hinh tru cd dudng cao la 3 127 A' , /- -> Didn tfch xung quanh ciia hinh lang tru la: (a)36V3; (b) 16V3 (c)46V3; (d )26 V3 Trd ldi (a) Cdu 14 Cho hinh lang tru luc giac ddu eanh day la 2V3 ndi tidp mdt hinh tru co dudng cao la 3 A A' / D' E' Dudng sinh cua hinh tru la (a)2V3; (b)3V3 (c)3; (d)6 Trd ldi (c) 128 Cdu 15 Cho hinh lang tru luc giac ddu canh day la 2V3 ndi tie'p mdt hinh tru cd dudng... Ggi y trd ldi cdu hdi 1 1 = OO' = 7cm Ggi y trd ldi cdu hdi 2 S^q=2Tirl = 2Ti.5.7 = 707i Ggi y trd ldi cdu hdi 3 Tinh thd tfch hinh tru V - 7 i r 2 h = 71.5^7 = 17571 caub 135 Hoat ddng cua GV Hoat ddng ciia HS Cdu hdi 1 Ggi y trd ldi cdu hdi 1 Tinh AB Tacd AI^ = O A ^ - O I ^ = 2 5 - 9 = 16 Do dd AB = 2AI = 8cm Cdu hdi 2 Ggi y trd ldi cdu hdi 2 TInh dien tich thie't didn Std=AB.OO' = 56cm^ Bai 6 Hudng... GV Cdu hdi I Xac dinh dudng sinh 1 Cdu hdi 2 Xac dinh ban kfnh r Cdu hdi 3 Xac dinh dudng cao ciia hinh tru Hoat ddng cua HS Ggi y trd ldi cdu hdi 1 1 =SA = 2a Ggi y trd ldi cdu hdi 2 r = OA = a Ggi y trd ldi cdu hdi 3 Dudng cao eiia hinh tru la : SO= aV3 Cdu hdi 4 Tfnh dien tfch xung quanh eua hinh tru 136 Ggi y trd ldi cdu hdi 4 1 2 S„„ xq = — 2 27ta.2a = 2Tia Cdu hdi 5 Ggi y trd ldi cdu hdi 5 Tfnh... day r= AI=^ cua hinh tru 2 Cdu hdi 2 Hay chi ra va tfnh dudng sinh cua hinh tru Cdu hdi 3 Ggi y trd ldi cdu hdi 2 I = AD = a Ggi y trd ldi cdu hdi 3 Tinh dien tfch xung quanh Svn xq = pi-l = 27 t —a 2 = 7ca Caub Hoat ddng cua GV Cdu hdi I Hoat ddng ciia HS Ggi y trd ldi cdu hdi I Hay chi ra va tfnh ban kfnh day AT ^ ciia hinh tru r = AI = — 2 119 Cdu hdi 2 Ggi y trd ldi cdu hdi 2 Hay cbl ra va tfnh dudng ... dudng cao la 126 Didn tfch toan phin ciia hinh ndn la: (a) I2T1V2 + 127 1; (b) 24 TIV2 + 127 I (c) 6TiV2 + 127 r; (d) 48TI^+12TI Trdldi (d) Cdu 12 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tie]... cua hinh ndn la: (a) I271V2 + 127 1; (b) 24 TiV2 + 127 t (c) 6TtV2 + 12Tt; (d) 487rV2 + 127 i Trdldi (d) Cdu 19 Cho hinh chdp luc giac ddu canh day la 2V3 ndi tiep mdt hinh ndn cd dudng cao la 154... 24 TtV2 153 (c) 671V2 ; (d) 487TV2 Trdldi (d) Cdu 11 Cho hinh chop luc giac ddu canh day la 2V3 ndi tie'p mdt hinh ndn cd dudng cao la Dien tfch toan phin cua hinh ndn la: (a) I271V2 + 127 1; (b) 24 TiV2