Question

aob is a diameter of the circle with center o and ac is a tangent to the the circle at a if boc =130 degree then find aco

Answer 1

see the attached file for solution. Thanks

Answer 2

angle OAC =90 angle between tangent and point of contact

Angle AOC = 180-130

=50

Angle ACO=180-(90-50)

=40

Therefore angle ACO =40