By definition the sum of the interior angles of any triangles is 180°
According to this add the measure of all the angles
[tex](x)+(x+7)+(2x+9)=180[/tex]simplify the equation and solve for x
[tex]\begin{gathered} 4x+16=180 \\ 4x=180-16 \\ 4x=164 \\ x=\frac{164}{4} \\ x=41 \end{gathered}[/tex]the first angle has a value of 41°
the second angle has a value of (41+7)° which is the same as 48°
the third angle has a value of (2*41 + 9) which is the same as 91°
