,,.:? : :AOC,ABC?,. 1 2.

AOB

DD

1

1 1 OC(AOBACB) ABAOB ACB

1 DE(ADBAEB) AB ACB ADB

1. B,D,E,ACABC,ADC,AEC.

: , ABO,CO(A,B),:ACB?,?:ACB,.:O ,DAOBACB ACB AOB18090

: , ABO,CO(A,B),:ACB?,?:ACB,.:O ,OA=OC=OB OCA = A, OCB= BA+ B+ ACB=1802 OCA+2 OCB=180 ACB= OCA+ OCB=90:,90(),90.:O ,AB,ACB=90,O ,ACB=90,ABO .

1.4_____________2. OBAC=32BOC=____

3.OACB = 130AOB=______

361446410023

11OCDC = DACB =90

3ACB =90

ABCDOABCDAC BD

4.,ABC,AB=AC,ABBCD,ACE.:BD=DE.5.ABC,ODAC,ABBCD,ACE.:BD=DE. 6.P49 9

7. 900 A.1 B.2 C.3 D.4ABCDEA+B+C+D+E A.1800 B.1500 C.1350 D.1200

9.,AB,O,C,EAC,OEACD,AC=8,DE=2,BC.