- Protractor
In
geometry , a protractor is a circular or semicircular tool for measuring anangle or acircle . The units of measurement utilized are usually degrees.Some protractors are simple half-discs; these have existed since ancient times. More advanced protractors, such as the Bevel Protractor have one or two swinging arms, which can be used to help measure the angle.
External Protractors are instruments used on spheres to find a certain number of degrees. There are all different types of protractors, and they are used to find angles.
Protractors are included as school supplies.
Bevel Protractor
A Bevel Protractor is a graduated circular protractor having a pivoted arm; used for measuring or marking off angles. Sometimes vernier scales are attached to give more accurate readings. It has wide application in architectural and mechanical drawing although with the availability of modern drawing software or
CAD the tool is less commonly used in that sphere.Universal Bevel Protractors are also used by toolmakers, as they measure angles by mechanical contact they are classed as mechanical protractors. [cite book
last = Farago
first = Francis T
authorlink =
coauthors = Curtis
title = Handbook of Dimensional Measurement
publisher = Industrial Press Inc
date = 1994
location =
pages = 580
url = http://books.google.co.uk/books?id=eVQPSr8nWekC&pg=PA255&lpg=PA255&dq=bevel+protractor+how+to+use&source=web&ots=5YQqaa7UOT&sig=6Ey33U8eNRPiBBYQe32nsoPyryQ&hl=en#PPA253,M1
doi =
id =
isbn = 0831130539]Gallery
See also
*
Protractor compass
*Goniometer
*Geometry template References
External links
*
* [http://www.ossmann.com/protractor/ More printable protractors]
* [http://www.mathopenref.com/constmeasureangle.html How to measure angles with a protractor] An interactive animation
* [http://www.mathopenref.com/constdrawangle.html How to draw angles with a protractor] An interactive animation
* [http://www.mathopenref.com/tocs/anglestoc.html Angle definition pages] with interactive applets that are also useful in a classroom setting. Math Open Reference
* [http://www.tradecombine.com/measuringinstruments/mitutoyo/miscellaneous/universalbevelprotractor.htm] Picture of bevel protector.
* [http://www.chandcoindia.com/products/measuring/steel_protractor.htm] Different bevel protectors.
* [http://its.foxvalleytech.com/MachShop1/Inspection/AngleMeas.htm Inspection Methods - Angular Measurement]
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