How To Use

Protractor Features
Our protractor is unique for a number of reasons. And anyone can learn to use it, usually very quickly!

You don't need to believe us about the protractor's quality, though - you can ask the teaches who use it!

Table of Contents:
Special Features
Comparison With A Standard Protractor
Comparison With "Swing-Arm" Protractors
Life-Long Guarantee




Special Features

Comparison With A Standard Protractor

How does our protractor measure up against the half-moon protractor? Here's a comparison.
Our Protractor
Standard Protractor
It's use is simple and intuitive. It is easy to learn how to use it.
Can be difficult to learn how to use. Double row of degrees often confuses students who may already be unsure of the concept of angles.
(Is this angle 70° or 110°? A student new to angles may not be sure.)








Can easily measure angles with short rays.
Cannot measure angles with short rays.
Is flexible and sturdy. (See our replacement policy.)
Is brittle, and often breaks in backpacks.
Can measure the length of rays easily. This also makes it easy to draw regular polygons (see our Draw A Regular Polygon lesson plan).
Cannot measure the length of rays without a ruler.


Can measure the reflex angle (the "outside" of an angle).
Cannot directly measure the reflex angle, since it only has 180° of measurement.
Comparison With "Swing-Arm" Protractors
Our protractor is able to measure and draw extremely acute angles, while most swing-arm protractors are not able to mesaure angles more acute than about 15°.

Our protractor is also a full-circle protractor, while most swing-arm protractors are only half-circle protractors.
Life-Long Guarantee
Our protractor is so sturdy and reliable that we guarantee it for life. If your protractor ever breaks, mail it to us and we'll mail you a replacement! Our mailing address is:

Barry Scientific
49 Lomita Drive
Mill Valley, CA 94941
About UsContact Us
49 Lomita Drive • Mill Valley, CA 94941 • (415) 381 5676 • (866) 301 3020 fax
camilla@barryscientific.com