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the minute hand on a watch is 1.5cm long. what distance does the tip of this hand travel through in 1 hour?

Guest Jul 10, 2014

Best Answer 

 #1
avatar+3450 
+13

Alright, here's my makeshift watch:

The red line is the rotation the minute hand makes in an hour. Note that my drawing isn't a perfect circle, but I believe the question is assuming that the rotation the minute hand makes is a full rotation.

We really just need to find the circumfrence of the red line, because that will tell us the distance that the tip of the minute hand travles in an hour.

We have the radius of this circle, and we need to find the circumference of the circle, but how do we do that?

We multiply the diameter of the circle by pi, and the diameter is 2r.

Our radius is 1.5, so our diameter is 3. (1.5*2)

$${\mathtt{3}}{cm}{\mathtt{\,\times\,}}{\mathtt{\pi}} = {\mathtt{9.424\: \!777\: \!960\: \!769\: \!379\: \!7}}{cm}$$

or rounded to the nearest tenth, 9.4 cm

NinjaDevo  Jul 10, 2014
 #1
avatar+3450 
+13
Best Answer

Alright, here's my makeshift watch:

The red line is the rotation the minute hand makes in an hour. Note that my drawing isn't a perfect circle, but I believe the question is assuming that the rotation the minute hand makes is a full rotation.

We really just need to find the circumfrence of the red line, because that will tell us the distance that the tip of the minute hand travles in an hour.

We have the radius of this circle, and we need to find the circumference of the circle, but how do we do that?

We multiply the diameter of the circle by pi, and the diameter is 2r.

Our radius is 1.5, so our diameter is 3. (1.5*2)

$${\mathtt{3}}{cm}{\mathtt{\,\times\,}}{\mathtt{\pi}} = {\mathtt{9.424\: \!777\: \!960\: \!769\: \!379\: \!7}}{cm}$$

or rounded to the nearest tenth, 9.4 cm

NinjaDevo  Jul 10, 2014
 #2
avatar+87333 
+3

I'm gonna' hire you as my "graphic artist"......ND.....that's a really neat picture.....(even if you did "borrow" it from another source!!!)

 

  

CPhill  Jul 10, 2014
 #3
avatar+3450 
+3

This one I actually drew up this one myself, that's why it doesn't look the best!

Thanks for the compliment though. :)

NinjaDevo  Jul 10, 2014
 #4
avatar+87333 
+3

Fooled me....looks pretty professional  !!!

 

 

  

CPhill  Jul 10, 2014
 #5
avatar+8258 
0

9.4 cm as the estimation of the really long number. NinjaDevo, I like your drawing. Looks professional. I thought that you got that from another website! LOL

   

DragonSlayer554  Jul 12, 2014
 #6
avatar+92806 
0

I like your pictures too Ninja, that is why i wanted you to put the progam that you use it the "information pages" thread.  It is unfortuate that putting it there will not automatically mean that we can all immediately use it as you do.  But, it would be a good start. Thumbs up from me too. 

Melody  Jul 12, 2014

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