Given the tangents at two points A and B on the circle x2+y2−4x+3=0 meet at origin O(0,0),
Plotting the diagram we get,

Now circle C:(x−2)2+y2=1
Equation of chord AB is given by T=0 i.e x×0+y×0−4(2x+0)+3=0
⇒AB:2x=3
Now OA=OB=02+02−4×0+3=3
So, AM=OA2−OM2=3−49=43=23
Now area of triangle OAB=21(2AM)(OM)
=433 sq. units