Expert: Paul Klarreich - 1/31/2008

Question
what is the diameter of a 5-inch pipe in centimeters? what is its radius in millimeters?

If I weigh 155 pounds, how or what is my mass in kilograms?


Answer
Questioner:   Alex
Category:  Advanced Math
Private:  No
 
Subject:  measurements and diameter
Question:  what is the diameter of a 5-inch pipe in centimeters? what is its radius in millimeters?

If I weigh 155 pounds, how or what is my mass in kilograms?
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Hi, Alex,

(Note: These questions belong in a different category. Advanced Math means Advanced Algebra, Trig, and Precalculus.  This is Basic Math.)

To convert from unit A to unit B, look up a conversion factor that says either:

1 of A = xxxx of B.

Then to convert A's to B's multiply by the xxxx.  
To convert B's to B's divide by the xxxx.  

Be sure to use your brain.  If the conversion says, for example:

1 A = 17.8 B's, then A's are bigger than B's.  So you should have FEWER A's than B's.  That will prevent you from making the error of dividing when you should multiply or vice versa.


what is the diameter of a 5-inch pipe in centimeters? what is its radius in millimeters?

Did you copy this question exactly as written?  Is the 5-inches really the diameter?  

I will assume you just meant to write:

What is 5 inches in centimeters?

Now 1 inch (it says here) = 2.54 cm.

So do 5 * 2.54.

Radius = 1/2 diameter = 2.5 inches.

Now 1 inch (it says here) = 25.4 mm.

So do 2.5 * 25.4

.......................


If I weigh 155 pounds, how or what is my mass in kilograms?

1 kg = 2.2 pounds.

I'll leave it to you to decide:
1. Which is bigger, a kilogram or a pound.
2. Whether to multiply or divide.

As to your question, "how is my mass in kilograms?", I think 155 pounds is very good.
I wish I could weigh that.