Angle made by arms of the clock
Now lets first take long arm of minutes
60 minutes makes 360 degree angle
Therefore 1 minute makes how much angle
Cross multiply and we get:
60 minutes ===== 360 degrees
1 minute ======== ? degrees
1 x 360 = ? x 60
Therefore ? degrees = 360/60 = 6
Thus 1 minute makes an angle of 6 degrees.
Example 1:
1) Find angle made by 30 minutes
1 minute ==== 6 degrees
30 minutes === ? degrees
Therefore ? x 1 = 6 x 30 = 180 degrees
Therefore angle made by 30 minutes is 180 degrees
2) Find angle made by 45 minutes
1 minutes ====== 6 degrees
45 minutes ====== ? degrees
Therefore ? x 1 = 6 x 45 = 270
Therefore angle made by 45 minutes = 270 degrees
Angle made by short arm (hour) of the clock
Now clock when it moves one hour the short arm moves 5 minutes on the clock
Therefore
1 minutes covers 6 degrees
5 minutes covers ? degrees
? = 5 x 6 = 30 degrees
Thus 5 minutes makes an angle of 5 x 6 = 30 degrees is the angle made by short arm while it moves one hour on the clock
Example 1 ) How much is the angle formed when clock moves 2.5 hours
Answer: Let us see 1hour move makes an angle 30 degree.
Therefore 2 hours makes 30 x 2 = 60 degrees
Remaining 1/2 hour by short arm makes 30(because 1 hour makes 30 degree ie covers 5 minutes)/2 = 15 degrees
Thus degree of angle formed by 2.5 hours is 60 + 15 = 75 degrees