I need help with this, please

Here's the solution,

the angles made by same arc on circle's circumference are equal.

So, Angle O = Angle P

( Angles made by arc NM )

=》

=》

=》

=》

now, value of angle at circumference :

=》

=》

=》

=》

and, we know that the angle made by an arc at center is double the angle made by same arc on its circumference,

so, measure of Arc NM

=》

=》

12

step-by-step explanation:

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