The sum of angle 3x and 45 is equal to 72. So equation for x is,
[tex]3x+45=72[/tex]Simplify the equation to obtain the value of x.
[tex]\begin{gathered} 3x+45=72 \\ 3x=72-45 \\ 3x=27 \\ x=9 \end{gathered}[/tex]Determine the measure of angle 3x.
[tex]\begin{gathered} 3x=3\cdot9 \\ =27 \end{gathered}[/tex]So value of x is 9 and measure of angle 3x is 27 degree.