The total angle of a triangle is equals to 180 degree. The triangle has 3 angles. we were given 2 angles as 20 degree each and asked to find the last angle. The last angle can be found below
[tex]\begin{gathered} 180-20-20\text{ =x} \\ x=180-40 \\ x=140^{\circ} \end{gathered}[/tex]The last angle is 140 degrees.