Answer:
The hour marks on a clock face are evenly spaced, 30° apart. To find the angle a line from the four o'clock mark to the twelve o'clock mark makes with a horizontal line, we need to count the number of hour marks between the two positions and multiply by 30°.
Starting from the four o'clock mark and moving clockwise to the twelve o'clock mark, we count 8 hour marks, including the one at the twelve o'clock mark. Multiplying 8 by 30°, we get:
8 x 30° = 240°
Therefore, the angle between the line from the four o'clock mark to the twelve o'clock mark and a horizontal line is 240°.