What is the measure of x?

Answer:
[tex]x = 24 {}^{o} [/tex]
Step-by-step explanation:
The angle x and BOC are supplementary, then
[tex]\widehat{BOC} + x = 180 {}^{o} \\ then \: \: 156 {}^{o} + x = 180 {}^{o} \\ hence \: \: x = 180 {}^{o} - 156 {}^{o} = 24^{o}[/tex]