Asked by  | 5th Dec, 2012, 07:37: PM

Expert Answer:

 
In quadrilateral OAPB
Angle P=80
Angle A=90
Angle B=90
therfor Angle O=360-(80+90+90)=100
 
Now in triAngle OAB
OA=OB
therfor   
Angle OAB=Angle OBA=X
 
X+X+100=180
X=40
 
therefor AngleOAB=40 degree

Answered by  | 7th Dec, 2012, 01:33: AM

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