Question

What is the angle measurement determined by the red piece

Answer 1

Notice that the sum of the angles adds up to 360°, therefore, we can set the following equation:

$x^{\circ}+100^{\circ}+80^{\circ}=360^{\circ}.$

Solving the above equation for x, we get:

$x^{\circ}=360^{\circ}-100^{\circ}-80^{\circ}.$

Finally, we get:

$x^{\circ}=180^{\circ}.$

Answer:

$180^{\circ}.$