How to find angle...

Discussion in 'Math' started by RRITESH KAKKAR, Dec 30, 2015.

  1. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    A clock shows the time as 12.20. What is the angle the hour hand makes with the minutes hand?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    It depends if you want to compensate for the hour hand, as it shifts a tiny bit every second.
    That is how a mechanical clock works.
    The minute hand makes 6 degrees every minute.

    Bertus
     
    RRITESH KAKKAR likes this.
  3. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    But it is wrong answer
     
  4. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    The minute hand makes 6 degrees every minute.
    6sec*5min*4=120 wrong
     
  5. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    In a mechanical clock, the hour hand moves with 1/60 of the speed of the minute hand.

    Bertus
     
  6. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    A clock shows the time as 12.20. What is the angle the hour hand makes with the minutes hand?

    The question is exactly what is the Angle now..


    upload_2015-12-30_19-50-15.png
     
  7. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
    Hello,

    I made a mistake in post #5.
    When the hour hand makes a 30 degrees move in an hour, it will make a move of 10 degrees in 20 minutes.

    Bertus
     
  8. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    When the hour hand makes a 30 degrees move in an hour, it will make a move of 10 degrees in 20 minutes.

    How?
    There is total 360 if anything go circle/round ...
    the answer is 110 degree why?
     
  9. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    Draw the analogue clock on a sheet of paper, but instead of the 12 hours, mark the 12 divisions in degrees, starting with 0 degrees at the top.

    The answer should become obvious if you remember to think carefully.

    Hint - the hour hand does not point to 0 degrees

    Over to you....
     
  10. Ramussons

    Active Member

    May 3, 2013
    557
    92
    The hour hand goes 360 degrees in 12 hours => 30 degrees /hour => 10 degrees in 20 minutes.
    The minute hand does 360 degrees in 60 minutes => 120 degrees in 20 minutes.

    => angle between the hands = (120 - 10) = 110 degrees.
     
  11. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    Here is The Clock
     
  12. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    That is a good start, but now draw it with the hour hand in the correct place...
     
  13. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    How?
     
  14. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    Look at a real analogue clock and see where the hands are at 12:20. Think about why the hands are where they are. Draw what you see and then work out the angle between hands.

    Play around with an analogue clock for a while adjusting the time manually and think about what is happening.

    Can't think what else to suggest.
     
  15. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    The Smaller hour hand goes to Top 12hour
    The bigger is at 4 because it is 20 min
    The right angle i.e. 12 hour hand and 15 min is 90 degree , plus more 5 min

    What else to do with it?
     
  16. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    The Smaller hour hand goes to Top 12hour - wrong - go and find a real clock and study it
    The bigger is at 4 because it is 20 min - correct

    Study a real clock and then try again
     
  17. bertus

    Administrator

    Apr 5, 2008
    15,649
    2,348
  18. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    Ok, i got it the 12 will move move towards 4/20min

    it is making 8degree per min why?

    upload_2015-12-31_15-30-1.png
     
  19. RRITESH KAKKAR

    Thread Starter Senior Member

    Jun 29, 2010
    2,831
    89
    it is making 8degree per min why?


    upload_2015-12-31_15-31-26.png
     
  20. hexreader

    Active Member

    Apr 16, 2011
    250
    82
    Sorry, but I must give in at this point.

    This is just too painful. :(
     
    shortbus likes this.
Loading...