we have
m∠DXB=[tex]70\°\ 15'\ 12''[/tex]
m∠DXC=[tex]30\°\ 30'\ 20''[/tex]
we know that
m∠DXB=m∠DXC+m∠CXB
so
m∠CXB=m∠DXB-m∠DXC
remember that
[tex]1\°=60'[/tex]
[tex]1'=60''[/tex]
so
m∠DXB=[tex]70\°\ 15'\ 12''[/tex]
convert one grade to minutes
m∠DXB=[tex]69\°\ 75'\ 12''[/tex]
convert one minute to seconds
m∠DXB=[tex]69\°\ 74'\ 72''[/tex]
Find the value of m∠CXB
m∠CXB=[tex](69\°\ 74'\ 72'')-(30\°\ 30'\ 20'')=39\°\ 44'\ 52''[/tex]
therefore
the answer is
the measure of angle CXB is equal to [tex]39\°\ 44'\ 52''[/tex]
