Mario places a laptop on a desk. He adjusted the screen so that the screen is at an angle of 81° with the desk.
We are asked to find the measure of the unknown angle x
Recall the straight-angle property,
The sum of angle x and angle 81° must be equal to 180°
So, we can write
[tex]x+81\degree=180\degree[/tex]
Let us solve the above equation for the unknown angle x
[tex]\begin{gathered} x+81\degree=180\degree \\ x=180\degree-81\degree \\ x=99\degree \end{gathered}[/tex]
Therefore, the unknown angle x is 99°
