Since, the circle passes through (3,4) and cuts the circle x2+y2=a2 orthogonally. ∴ (x−3)2+(y−4)2=0 .......(i) Also, x2+y2−a2=0 ........(ii) ∴ Equation of radical axis, (x−3)2+(y−4)2−(x2+y2−a2)=0 ⇒ x2−6x+9+y2+16−8y−x2−y2+a2=0 ⇒ 6x−8y+25+a2=0 ⇒ 6x−8y−25−a2=0 ........(iii) Now, the distance from (0,0) to Eq. (iii), we get