Step-by-step 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:
![2x+100=180](https://img.qammunity.org/2023/formulas/mathematics/college/5qt42pn01hkr5s6pfjehbbc3otknft7zwj.png)
We can substract 100 from both sides of the equation:
![\begin{gathered} 2x+100-100=180-100 \\ 2x=80 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/g6nqrdk0zaz29mllpj5atqeezwlk0ujjmp.png)
Then we divide both sides by 2:
![\begin{gathered} (2x)/(2)=(80)/(2) \\ x=40 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/4lidn5mxkqwngklbx0a0euxsoguqep3lj5.png)
Answer
Then the answer is 40.