. . , - . .
, , 20 | , , 20 |
.
.
.
, :
- 180
CAB = 20, ABC = 180 - 90 - 20 = 70
COA - , - . ∠OCA = ∠OAC = 20º
BKC - , BCK = 180 - 90 - 70 = 20
BCA - , BCK, KCO OCA. :
20 + 20 + ∠KCO = 90
∠KCO = 50
: 50 .
. . , - . .
. , , , , 3 4 .
AC BC 2x 2y. ,
AC2 + CD2 = AD2
AC = 2x, CD = y ( ),
4x2 + y2 = 9
,
EC2 + BC2 = BE2
EC = x ( ), BC = 2y,
x2 + 4y2 = 16
.
.
5x2 + 5y2 = 25
5(x2 + y2) = 25
x2 + y2 = 5
AC2 + BC2 = AB2
4x2 + 4y2 = AB2
4 (x2 + y2) = AB2
x2 + y2 = 5
AB2 = 20
AB = √20 = 2√5
: 2√5
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. , 180 , .