Page 131 - NUMINO Challenge_D1
P. 131
15 Angles and Time
Basic Concepts Clock Hands Form Angles
The minute hand rotates 360 in 1 hour, therefore it rotates 360 60 6
per minute.
The hour hand rotates 360 in 12 hours, therefore it rotates 360 12 30
per hour, and 30 60 0.5 per minute.
In 1 minute, the minute hand rotates 6 and the hour hand rotates 0.5 .
Therefore, the minute hand rotates 5.5 more than the hour hand per
minute.
Example The clock below shows 4:35. Find the angle formed by the clock
hands.
11 12 1
10 2
93
84
765
Class Notes
If the hour hand points to 4 and the minute hand points to 7, the angle 11 12 1
10 2
that is formed by the clock hands is . 93
84
When the minute hand moves from 4:00 to 4:35, the hour hand moves
as well. Since the hour hand moves 0.5 per minute, it moves 765
in 35 minutes. 11 12 1
10 2
Therefore, the angle formed by the clock hands at 4:35 is 93
. 84
765
Try It Again The clock reads 6:40. Find the angle formed by the clock hands.
11 12 1
10 2
93
84
765
128 NUMINO Challenge D1
Basic Concepts Clock Hands Form Angles
The minute hand rotates 360 in 1 hour, therefore it rotates 360 60 6
per minute.
The hour hand rotates 360 in 12 hours, therefore it rotates 360 12 30
per hour, and 30 60 0.5 per minute.
In 1 minute, the minute hand rotates 6 and the hour hand rotates 0.5 .
Therefore, the minute hand rotates 5.5 more than the hour hand per
minute.
Example The clock below shows 4:35. Find the angle formed by the clock
hands.
11 12 1
10 2
93
84
765
Class Notes
If the hour hand points to 4 and the minute hand points to 7, the angle 11 12 1
10 2
that is formed by the clock hands is . 93
84
When the minute hand moves from 4:00 to 4:35, the hour hand moves
as well. Since the hour hand moves 0.5 per minute, it moves 765
in 35 minutes. 11 12 1
10 2
Therefore, the angle formed by the clock hands at 4:35 is 93
. 84
765
Try It Again The clock reads 6:40. Find the angle formed by the clock hands.
11 12 1
10 2
93
84
765
128 NUMINO Challenge D1
