Move the on-screen protractor using (desktop) left mouse drag or (tablet) single finger touch and drag. Protractor is highlighted in green when moving. Follow the other ray up to the measurements on the protractor's arc. Use the scale measurements that are increasing in the direction that your angle is opening up in. If it’s an acute angle, make sure you’re looking at the measurements that are less than 90°. If your angle is obtuse, use the scale with measurements greater than 90°. The number that the ray passes through is your angle’s measurement in degrees. [5] X Research source For pupils needing more general support on angle work, follow the link below for a superb learning resource: Modern rehabilitative therapy motion capture systems perform goniometry at the very least measuring active range of motion. [11] While in some cases accuracy may be inferior to a goniometer, measuring angles with a motion capture system is superior at measuring during dynamic, as opposed to static situations. Furthermore, using a traditional goniometer takes valuable time. In the clinical context, performing manual measurements takes valuable time and may not be practical.

Reflex Angles: Reflex angles measure more than 180 degrees but less than 360 degrees.They are often used in navigation and surveying, as well as in sports and recreation.For example, a football field is marked with reflex angles to indicate the end zones. Farago, Francis T; Curtis (1994). Handbook of Dimensional Measurement. Industrial Press Inc. p.580. ISBN 0-8311-3053-9. A positioning goniometer or goniometric stage is a device that rotates an object precisely about a fixed axis in space. It is similar to a linear stage— however, rather than move linearly relative to its base, the stage platform rotates partially about a fixed axis above the mounting surface of the platform. Positioning goniometers typically use a worm drive with a partial worm wheel fixed to the underside of the stage platform meshing with a worm in the base. The worm gear may be rotated manually, or by a motor in automated positioning systems. Jones, A (2014). "Concurrent validity and reliability of the simple goniometer iphone app compared with the universal goniometer" (PDF). Physiotherapy: Theory and Practice. 30 (7): 512–516. doi: 10.3109/09593985.2014.900835. hdl: 2328/37026. PMID 24666408. S2CID 28719817. Jones, Sealey (2014). "Concurrent validity and reliability of the simple goniometer iPhone app compared with the universal goniometer" (PDF). Physiotherapy: Theory and Practice. 30 (7): 512–516. doi: 10.3109/09593985.2014.900835. hdl: 2328/37026. PMID 24666408. S2CID 28719817.

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place it so that one side of the angle lines up with one of the zeros, and read that set of numbers. Use a protractor to measure the angle on the right-hand endpoint of the given side, mark it with a cross and draw a line from the endpoint through this mark.

Solution: Align the protractor with the vertices of △ABC. Note the angle obtained in each case. You will find that all the angles of the equilateral triangle measure 60°.Angles Glossary Acute Angle Any angle that is less than 90° Right Angle An angle that is 90° Obtuse Angle An angle greater than 90° but less than 180° Straight Angle An angle of 180° which makes a straight line Reflex Angle An angle greater than 180° Related activities

So whether you want to measure an angle, measure the degree, or compare two angles, the online protractor is the perfect tool for the job! Measuring angles with the online protractorProtractors typically label measurements in 10s, but between each number are little lines that represent 1°. If your ray falls in between 2 whole numbers, like 50° and 60°, just count the lines to find your angle’s exact measurement. [6] X Research source Main article: Positioning goniometer A miniature electro-mechanical goniometer stage. This type of stage is used primarily in the field of lasers and optics. Milanese, Gordon. "Reliability and concurrent validity of knee angle measurement: Smart phone app versus universal goniometer used by experienced and novice clinicians". Manual Therapy. 5: 1–6. The bevel protractor is used to establish and test angles to very close tolerances. It reads to 5 arcminutes (5′ or 1 / 12°) and can measure angles from 0° to 360°. Using a ruler, measure along the line drawn from the left hand endpoint to the cross and mark the length of the other given side on it.