Explanation
The sum of the three internal angles of a triangle is always equal to 180°. Let's use x for the measure of each of the missing angles. Then the sum of the three angles of triangle ABC is expressed as x+x+100°=2x+100°. If we equalize this expression to 180° we obtain an equation for x:
[tex]2x+100=180[/tex]
We can substract 100 from both sides of the equation:
[tex]\begin{gathered} 2x+100-100=180-100 \\ 2x=80 \end{gathered}[/tex]
Then we divide both sides by 2:
[tex]\begin{gathered} \frac{2x}{2}=\frac{80}{2} \\ x=40 \end{gathered}[/tex]Answer
Then the answer is 40.
