Interior angles of a triangle add up to 180, this imply that
[tex](y-10)+4y+20=180[/tex]
Now, by combining similar terms, we have
[tex]y+4y-10+20=180[/tex]
which gives
[tex]5y+10=180[/tex]
If we movw +10 to the right hand side as -10, we obtain
[tex]\begin{gathered} 5y=180-10 \\ 5y=170 \end{gathered}[/tex]
then, y is equal to
[tex]\begin{gathered} y=\frac{170}{5} \\ y=34 \end{gathered}[/tex]
Now, we can substitute this values in order to find the measure of each angle:
[tex]\begin{gathered} (y-10)\Rightarrow34-10=24 \\ \text{and} \\ 4y\Rightarrow4(34)=136 \end{gathered}[/tex]
Therefore, the angles are 24, 136 and 20 degrees.
