Vertical angles are pairs of angles that are opposite each other when two lines intersect. Vertical angles are always equal in measure.
Let the measure of each angle be \( x \). Since they are vertical angles and their sum is given as 300°, we can write the equation:
\[ x + x = 300° \]
This simplifies to:
\[ 2x = 300° \]
Now, divide both sides by 2:
\[ x = 150° \]
Thus, the measure of each angle is 150°.