not to bore you to death with the "inscribed quadrilateral conjecture", but you can search for that in google, and I can even include a quick proof of it
in short what "inscribed quadrilateral conjecture" means, opposite angles, in an inscribed quadrilateral in a circle, are "supplementary angles"
meaning D + B = 180 and A + C = 180
[tex]\bf \measuredangle A + \measuredangle C = 180\implies A+74=180\implies A=180-74\implies \boxed{A=106}[/tex]
