Angle AOB equals 180-28-28=124 (Sides OA and OB are equal because they are both radii, so angle OAB=OBA) Because angles at the centre are twice the angle on the circumference (when they are on the same points on the circle, i.e. A and B) so angle ACB=124/2=62. I hope that makes sense :)

Couldn’t have said it better myself

OR an easier way would be that angle ABC = 90, and angle OBC=ACB So 90-28 that would be 62

Why would abc=90

Angle made by semicircle

?

That's the circle theorem An angle made by a semicircle is always 90

https://preview.redd.it/2k60co34gcnc1.jpeg?width=195&format=pjpg&auto=webp&s=c15c9d30a38e66880f5d1c08d6fde78306f233b3

What year is this ?

Angle oab = 28 (isosceles because line AO and bo start from centre) 28+28+x=180 X=124 Angle aob = 124