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Reading a Protractor

Date: 9/8/96 at 22:29:58
From: Bob Vanselow
Subject: Reading a Protractor

Which side of a protractor scale do you use?

Date: 9/9/96 at 11:39:23
From: Doctor Robert
Subject: Re: Reading a Protractor

I think that the easiest way to decide which scale to use is to look
at the angle you're measuring.  If it is greater than a right 
angle (more than ninety degrees) then use the scale that has numbers 
greater than 90. If the angle is obviously acute (measures less than 
90 degrees), use the scale which has numbers less than 90.  

Of course you have to line up the protracter correctly with the center 
point on the vertex of the angle and one of the rays of the angle 
coincident with the line on the protracter.

Happy measuring!

-Doctor Robert,  The Math Forum
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Associated Topics:
Middle School Geometry
Middle School Measurement
Middle School Two-Dimensional Geometry

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