Need ! in the diagram of circle o, what is the measure of abc?

54 degrees

Step-by-step explanation:

I would turn this into a quadrilateral by connecting C to O and O to A.

The angles of a quadrilateral add up to 360 degrees.

So we have 90+90+126+angleABC=360

                            180+126+angleABC=360

                                  306+angleABC=360

                                           angleABC=360-306=54

ABC = 54°

Step-by-step explanation:

Two tangent have been drawn from an external point B to the circle O.

These tangents touch the circle at points A and C.

Now as per Theorem of arcs and angles.

∠ABC =   [m(major arc AC) - m(minor arc AC)]

          =  [234 - 126]

         =  × (108)

         = 54°

Therefore, ABC = 54°

12

step-by-step explanation:

a triangle's   full angle is 180 degrees so 180 - 156 = 24. 24/2=12