Verified answer

Answer: 180-52=128

as angleA and angleC add up to make a supplementary angle and ABOC make up a quadrilateral thus angleB and angleO should add up to make a supplementary angle too

Solution

In ΔAOC and ΔOBC, we have

OC=OC        [Common]

OA=OB       [Radii of the same circle]

CA=CB        [Tangents to a circel]

Hence , ΔOAC≅ΔOBC by SSS congruence criterion Thus, ∠ACO=∠BCO=300