During the motion of hour hand and minute hand from 1:00 pm to 10:00 pm, the number of right angles formed is this period is:

During the motion of hour hand and minute hand from 1:00 pm to 10:00 pm, the number of right angles formed is this period is:
Answer: 18

From 1:00 pm to 10:00 pm (9 hours), the hour and minute hands form two right angles per hour (at approximately 15 and 45 minutes past). Thus, (9 \cdot 2 = 18). Studying this highlights clock geometry, providing lessons on applying angles to time-based problems.