. , , .
n- 180(n-2).
.
, 180 .
A 1 A 2... A n , n > 3. A 1. n 2 : Δ A 1 A 2 A 3, Δ A 1 A 3 A 4,..., Δ A 1 A n 1 A n. . 180, (n 2). n - A 1 A 2... A n 180 (n 2).
.
80 , - 150 . ?
.
.
: n- 180(n-2).
, :
180(n-2)=3*80+x*150,
3 80 , , x.
, n, , , x=n-3.
:
180(n-2)=240+150(n-3)
180n - 360 = 240 + 150n - 450
180n - 150n = 240 + 360 - 450
30n = 150
n=5
: 5
.
, 120 ?
.
.
: n- 180(n-2).
, . , , 120 . :
180(n-2)=120n
180n - 360 = 120n
180n - 120n = 360 ( )
60n = 360
n=6
, : 120 , .
:
180n - 120n = 360, , 120n, 60n. , .
: .
113 , - . .
|
|
.
.
: n- 360.
,
3*(180-113)+(n-3)x=360
- , , ( , n-3, ) x.
201+(n-3)x=360
(n-3)x=159
159 53 3, 53 - . .
, n-3 = 3, n=6, - .
:
, .
, 3600. . , , , 4*900 = 3600. . .
.
, :
1)120
2)60
3)72
.
- , .
, , - . , .
360 .
, , :
1) 360 / 120 = 3 ( )
2) 360 / 60 = 6 ( )
3) 360 / 72 = 5 ( )
: 3; 6; 5 .
. ( , ). , - . " " sqrt(), sqrt - , . "√".
.
24 2. .
.
, .
24 / 6 = 4 2
() ,
a = √4 = 2
S = a3 = 23 = 8 3.
: 8 3.
. ( ). , - . " " sqrt(), sqrt - , . "√"
KM α β M1 2, - 1 2 . 12,
1 = 8.
1 1: 2 2 = 4: 9
|
|
.
, , , KM1P1 KM2P2.
K, , α β , 1 1 2 2, , . , , , KM1P1 KM2P2 - . .
KM1P1 KM2P2 ,
1 1 / 2 2 = 1 / K2
K2 . :
4 / 9 = 8 / x
4x = 72
x = 18
: 18
, α β, l m. l A B 1 2 , m - 1 2. 22, 11 = 12, 1:2 = 3:4
.
12 12 , 11 22.
11 22 . , - . 11 22 .
.
:
1:2 = 11:22,
:
22 = 4 * 12 / 3 = 16
: 16 .
( 2)
. ( ). , - . " " sqrt(), sqrt - , . "√"
, , b. 1 2, b B1 B2 .
KB2 A2B2 A1B1 4:3, KB1 = 14 .
.
a b , . A2KB2 A1KB1. , , , KA2 KB2 A1B1 A2B2, - .
, , :
KB2: KB1 = 4:3
KB2: 14 = 4:3
KB2 = 14 * 4 / 3 = 56/3 = 18 2/3
: 18 2/3