Answer:
To work out the size of angle \( x \), we need to consider the angles in the diagram.
\[ x = 180^\circ - \angle ABC \]
\[ x = 180^\circ - (100^\circ + 80^\circ) \]
\[ x = 180^\circ - 180^\circ \]
\[ x = 0^\circ \]
So, \( x = 0^\circ \).
Reasoning:
\[ x = 180^\circ - \angle ABC \]
\[ x = 180^\circ - (100^\circ + 80^\circ) \]
\[ x = 180^\circ - 180^\circ \]
\[ x = 0^\circ \]
The reasoning is based on the fact that the sum of angles in a straight line (180 degrees) subtracted from the known angles in the diagram results in \( x \).
