# Tutor.com Geometry Session

##### Mar. 31, 2012

Session Transcript - Math - Middle Grades, 3/1/2012 9:13PM - Tutor.comSession Date: 3/1/2012 9:13PM
Length: 12.8 minute(s)

System Message
[00:00:00] *** Please note: All sessions are recorded for quality control. ***

Guest (Customer)
[00:00:00] nick claus plans to have a model train running in a circle around his holiday tree. how many feet of track will he need if the diameter of the circle is 9.5 ft? round to the nearest whole number

Tahna O (Tutor)
[00:00:07] Hi! Welcome to Tutor.com

Guest (Customer)
[00:00:26] hey(:

Tahna O (Tutor)
[00:01:01] okay, what we're looking for here is the distance around the circle. Do you remember what that's called?

Guest (Customer)
[00:01:31] circumfrance

Tahna O (Tutor)
[00:02:08] perfect and the formula for circumference is 2 pi r, but they gave us the diameter instead of the radius right?

Guest (Customer)
[00:02:32] yes just diameter

Tahna O (Tutor)
[00:03:01] do you remember how to find the radius by using the diameter?

Guest (Customer)
[00:04:02] yes you can divide the radius by 2 because the radius times to becomes the diameter right?

Tahna O (Tutor)
[00:04:25] right! great! so 9.5 divided by 2 is?

Guest (Customer)
[00:04:56] 4.75

Tahna O (Tutor)
[00:05:01] perfect

Guest (Customer)
[00:05:09] so what now

Tahna O (Tutor)
[00:05:41] so now we plug 4.75 into our equation and solve
[00:05:47] so 2 times pi times 4.75 is about?
[00:06:45] okay let's not do that
[00:07:04] the c is already by itself. All we have to do now is multiply 2 times pi times 4.75

Guest (Customer)
[00:08:00] sorry i figured out my problemi need to divide by 3.14 correct?

Tahna O (Tutor)
[00:08:13] no, don't divide at all

Guest (Customer)
[00:08:18] why not

Tahna O (Tutor)
[00:08:26] just multiply 2 times 3.14 times 4.75

Guest (Customer)
[00:09:00] why i thought the to undo multiplication you would divide cause its the oppisite

Tahna O (Tutor)
[00:09:12] because c is already by itself, which is exactly what we want. We're trying to find C
[00:09:32] we don't need to undo anything because C is already alone on one side of the equation
[00:09:57] just simplify multiply 2 times 3.14 times 4.75

Guest (Customer)
[00:10:06] okay ithink i get it

Tahna O (Tutor)
[00:10:14] okay
[00:10:33] give it a try, what do we get if we multiply 2 times 3.14 times 4.75?

Guest (Customer)

Tahna O (Tutor)
[00:11:08] great! yes, now we need to round to the nearest whole number

Guest (Customer)
[00:11:34] soooo it would be 30?

Tahna O (Tutor)
[00:11:48] exactly! great work!

Guest (Customer)
[00:12:11] thanks nope (:

Tahna O (Tutor)
[00:12:20] okay have a great night!
[00:12:24] Thanks for using Tutor.com.Â Please fill out the survey as you leave so we can learn how we can better help you in the future!Â
[00:12:26] Bye!

Guest (Customer)
[00:12:32] thanks you too(: