=0 Length of tangents drawn from external point to the circle is √S1. Now, according to the question, Let length of tangents drawn from point (1,2) to circles C1 and C2 are L1 and L2 respectively. So, L1=√S1=√12+22+1+2−4 =√1+4+3−4=√4 L2=√S1′=√12+22−