Math Is Fun Forum

mukesh

Member

Registered: 2010-07-18

Posts: 31

measurment of angle

find the angle between the minute hand and the hour hand of a clock at quarter to twelve

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: measurment of angle

Hi mukesh

See the picture below.Let us call the angle between the clock hands x,the angle between the hour hand and 12 o'clock mark-y and the angle between the minute hand and 12 o'clock mark-z.

We can see that x=z-y.

Now let us see how much are y and z.

z is a quarter of a full circle,so it is 90 degrees.

y is the quarter of the angle between the 11 o'clock mark and the 12 o'clock mark,and the angle between the 11 and 12 o'clock marks is one twelfth of the full circle so it is 360/12.Because y is 1/4 of that angle,we have that y is:

and because x=z-y we have:

x=z-y=90°-7.5°=82.5°

This means the angle we are looking for is 82.5°.

If you have any more questions,feel free to post them.

Last edited by anonimnystefy (2012-04-22 19:38:04)

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“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

mukesh

Member

Registered: 2010-07-18

Posts: 31

Re: measurment of angle

thanks fr it,plse be always with me,i really need a help
Plse post ans,if i ask in future

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: measurment of angle

Hi mukesh

I will try.I may not always be able to help,but there will always be some of the other guys to help you.

Did you understand the solution? Tell me if you have any doubt.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,143

Re: measurment of angle

hi Stefy,

A very clear explanation.  Have you considered becoming a teacher? 

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

mukesh

Member

Registered: 2010-07-18

Posts: 31

Re: measurment of angle

no i got it nw,thanks again.
Plse response fr my future questions

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: measurment of angle

Hi mukesh

Ok!

Hi Bob

Have you considered becoming a teacher?

No disrespect,but,no,thank you! I see what my parents go through when making plans for class. And all the test marking. And the protests about salary of teacher that we have here.

But thanks for the compliment,though I think it was over exaggerated.

---

“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.

Bob

Administrator

Registered: 2010-06-20

Posts: 10,143

Re: measurment of angle

Arhhh.  That makes sense.  Your parents are teachers.  So it's "in the blood".  Maybe you will defy heredity and maybe you won't.  I'll wait and see. 

Bob

---

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: measurment of angle

Hi Bob

Oh,I just remembered something when you said that "in the blood".Let me send you an e-mail.I don't really want to discuss it publicly.

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“Here lies the reader who will never open this book. He is forever dead.
“Taking a new step, uttering a new word, is what people fear most.” ― Fyodor Dostoyevsky, Crime and Punishment
The knowledge of some things as a function of age is a delta function.