30
36
40
72
Correct answer is A
In the diagram above, \(\alpha\) = 2mo (angle at centre = 2 x angle at circumference)
\(\alpha\) + 10mo = 360o (angle at circumference)
\(\alpha\) + 10mo = 360o(angles round a point)
2mo + 10mo = 360o
12mo = 360o
mo = \(\frac{360^o}{12}\)
= 30o