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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?

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1592
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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?

Jul 10, 2014

#1
+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

Jul 10, 2014

#1
+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

#2
+94619
+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!!!)

Jul 10, 2014
#3
+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. :)

Jul 10, 2014
#4
+94619
+3

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

Jul 10, 2014
#5
+8263
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

Jul 12, 2014
#6
+95369
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.

Jul 12, 2014