I will fan and medal. Freddie is at chess practice waiting on his opponent's next move. He notices that the 4-inch-long minute hand is rotating around the clock and marking off time like degrees on a unit circle. Part 1: How many radians does the minute hand move from 3:35 to 3:55? (Hint: Find the number of degrees per minute first.) Part 2: How far does the tip of the minute hand travel during that time? You must show all of your work.
how many minutes in an hour?
60
and how many degrees in a circle?
360
so how may degrees per minute?
6
actually since your question is given in radians, we can forget about degrees
or, now that you have 6 degrees, we can convert the 6 degrees to radians do you know how to do that?
i dont know how to do that
put it over \(180\) and multply by \(\pi\) i.e.. \[6^\circ=\frac{6\pi}{180}\] which you can reduce
i mean reduce the fraction, leave the \(\pi\) there
so for number 1 its 30?
no
on minute is \[\frac{\pi}{30}\] radians
for 20 minutes, multiply that by 20
im confused what i multiply by 20
lets go slow
is it clear that from 3:35 to 3:55 is 20 minutes?
yes
and it is also clear that 20 minutes is one third of an hour?
yes
and do you know that the entire circle, one complete rotation, is an angle of \(2\pi\)?
yes
so your 20 minutes is one third of that
so what should i type for the first one? I put there is 20 minutes in between
i have no idea what you should type in for what the answer to the first question "How many radians does the minute hand move from 3:35 to 3:55? " is \[\large \frac{2\pi}{3}\]
ok
since twenty minutes is one third of 60 minutes, and two pi divided by 3 is what i wrote above
thank you. i will be right back let me type this up in my own words
How far does the tip of the minute hand travel during that time? the hand if 4 inches long multiply the result above by 4
ok im back.
ok we are done right?
need help for the second please
i wrote the answer above `
4 inches long?
the angle is actually defined by the arc length over the radius your radius is 4 and your angle is \(\frac{2\pi}{3}\) therefore the arc length is the product of those two numbers
divide 2pi/3 by 4 to get the arc length?
"product"
aka multiply
8.37?
i would just write \[4\times \frac{2\pi}{3}=\frac{8\pi}{3}\] and leave it at that
thank you so much i understand now
yw
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