2 2circles intersect at a and b
the line formed by their centers(o and p) is the perpendicular bisector of chord ab
con.tri. oap and obp
oa=ob (radii of same circle)
therefore, oap is cong. to obp by SSS
let m the point of intersection of ab and op
aom=bom (proved by CPCT)
therefore tri. aom is cong. to bom by sas
now ang. amo+bmo=180 (linear pair)
lly we can prove it for the other two.
i.e all angles formed r 90
HENCE THE PROOF..