Uchburchak yuzi
a ha
b hb
c hc 1
a2Sinβ Sinγ
S , S abSinγ ;
2 2 2 2 2 Sinα
S p( p a)( p b)( p c) (Geron formulasi);
S abc pr ,
S
p a b c ;
, m ma mb mc .
2
Uchburchakdagi asosiy teoremalar
Sinuslar teoremasi:
a Sinα
b Sinβ
c Sinγ
2R ,
R – tashqi chizilgan aylana radiusi.
Kosinuslar teoremasi:
a2 b2 c2 2 bcCosα .
a bCosγ cCosβ .
Molveyde formulasi: 5. Tangenslar teoremasi
a b
Cosα β
2 .
a b
tg α β
2
ctg γ
2 .
c Sin γ
a b tg α β tg α β
2
6. Sinα ;
2
2 2
Cosα .
2
Teng yonli uchburchak
hc
; S c ;
2 4
a2
R ;
2hc
r c 2a c .
4hc
1) а2 в2 с2
To‘g‘ri burchakli uchburchak
(Pifagor teoremasi);
2) Sinα b , Cosα a ; tgα b , ctgα a ;
c c a b
3) a2 ca, b2 cb;
h2 ab,
h ab ;
с c
4) R c m ,
r a b c ,
r R a b ;
2 c 2 2
ab ch a2tgα c2Sin2α 2
d 2
c
6)
b ,
a
y 2
x
b ,
a
l – bissektrisa.
R 3a , r 3a ,
Teng tomonli uchburchak
R 2r ;
3 6
h 3r 1,5 R r R,
S 3 a2 .
4
To‘rtburchaklar Kvadrat
P 4a ,
S a2 d ,
2
2
d a ,
r a ,
2
R d .
2
To‘g‘ri to‘rtburchak
P 2(a b) , S ab ,
d ,
R d .
2
Parallelogramm
1 2
1) P 2(a b) ; 2) 2a2 2b2 d 2 d 2 ;
3) S a h a b Sinα , S 1 d d Sinϕ .
a 2 1 2
1) 4a2 d 2 d
2 ; 2)
Romb
S a h 2a r 1 d d ,
1 2
S a2 Sinα ; 3)
h 2r .
2 1 2
Trapetsiya
S mh 1 d d Sinϕ ;
2 1 2
d1 ab
3) S2 S4
c2a d 2b a b ;
,
S
2 .
4) AE=EC, BF=FD;
MN a b
2
EF a b ,
–o‘rta chiziq;
ME FN b ; AO OD a .
2 2 OC OB b
Teng yonli trapetsiya
b a2
x ,
2
c2 h2 ;
4
S 1 d 2Sinα a b h ; 2 r h .
2 2
To‘g‘ri burchakli trapetsiyada
1 2
d 2 d 2 a2 b2 .
Aylanaga tashqi va ichki chizilgan to‘rtburchaklar
Aylanaga tashqi chizilgan to‘rtburchak
a c b d ;
S pr ( a c) r ( b d ) r , bu yerda 2 p a
Aylanaga ichki chizilgan to‘rtburchak
α β γ φ 180;
ad bc d1 d2 ;
S p a p b p c p d ;
R 1 4S
ab cd ac bd ad bc .
Ko‘pburchaklar
Ichki burchaklari yig‘indisi: n 2π ;
Tashqi burchaklari yig‘indisi: 2π ;
Diagonallari soni:
nn 3
2
ta.
Ichki burchagi: n 2π
n
Tashqi burchagi: 2π ;
n
Muntazam ko‘pburchaklar
;
4) Sn 2 4 ;
5) a 2R Sinπ 2r tg π .
n n
Muntazam beshburchak, oltiburchak, sakkizburchak Muntazam beshburchak
Ichki burchaklari yig‘indisi: 540 ;
Ichki burchagi: 108 ; Tashqi burchagi: 72 ;
a R
2
10 2 5 2r ;
R a
r 1; r R 1 a ;
10 4 10
d 1
a , d – diagonal;
S 5 R2
a2
25 10 5 5r 2 .
2 8 4
Muntazam oltiburchak
Ichki burchaklari yig‘indisi 7200;
Ichki burchagi: 120 ; Tashqi burchagi: 60 ;
a R 2 r
3
; r a 3 ;
2
d1 a ,
d2 2R 2a ;
S 3 R2 3 a2
2r 2 .
2 2
Muntazam sakkizburchak
Ichki burchaklari yig‘indisi 1080 ;
Ichki burchagi: 135 ; Tashqi burchagi: 45;
a R
R a
2
2 r
r
1 ;
;
r R
2
a
1;
d1 a 2 2 ; d2 a 1
2 ;
d3 2R a ;
S 2R2 2a2
1 8r2
1.
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