Tiet 58 Hinh hoc 9-Hinh tru.ppt

Ch¬ngIV:H×nh trô
H×nh nãn H×nh cÇu–
1/H×nhtrô
§¸y
§©ulµ®¸y?
§©ulµmÆtxungquanh?
§©ulµ®êngsinh?
MÆtxungquanh
§êngsinh
10cm
8cm
11cm
7cm
1cm 3cm
H×nha H×nhb H×nhc
ChiÒucao?,b¸nkÝnh®¸y?
Bµi3(110)
Ph¶ich¨ngmÆtníctrongcècvµmÆtníctrong
èngnghiÖmcãd¹ngh×nhtrßn?
B
A
ChiÒudµih×nhch÷nhËtb»ngchuvi®¸y=2π.5(cm)
DiÖntÝchh×nhch÷nhËtlµ:10.10π=100π(cm
2
)
DiÖntÝchmét®¸ylµ:π.5
2
=25π(cm
2

)
DiÖntÝchtoµnphÇnh×nhtrôlµ:100π+25π.2=150π(cm
2
)
5cm
10cm
DiÖntÝchxungquanhh×nhtrôlµ:S
xq
=2πrh
DiÖntÝchtoµnphÇnh×nhtrôlµ:S
tp
=2πrh+2.πr
2
ThÓtÝchh×nhtrôlµ:V=S
®¸y
.h=πr
2
h
r
h
Chuvi®¸y
h
a
b
TÝnhthÓtÝchvßngbi(phÇn gi÷a hai h×nh trô)
C¸ckÝchthícghitrªnh×nhvÏ
Bµi5(111)
H×nh
B¸n
kÝnh

ChiÒu
cao
Chuvi
®¸y
D.tÝch
®¸y
D.tÝch
XQ
ThÓ
tÝch
1 10
5 4
8
4π
2π π 20π 10π
10π 25π 40π 100π
2 4π 32π 32π
V=V
2
–V
1
=πa
2
h-
=πh(a
2
-b
2
)
πb

2
h
10cm
8cm
11cm
7cm
1cm 3cm
H×nha H×nhb H×nhc
TÝnhdiÖntÝchxungquanhvµthÓtÝch
Méth×nhtrôcãb¸nkÝnh®¸ylµ7cm,diÖntÝch
xungquanhlµ352cm
2
.Khi®ãchiÒucaolµ:
A/3,2cm B/4,6cm C/1,8cm
D/2,1cm E/MétkÕtqu¶kh¸c
ChänmétkÕtqu¶®óng?
HíngdÉn:BTVN1,2,6,7,8,9