VIDEOS 1 TO 50

Measuring angles - Degrees and Protractors

Published: 2016/08/18

Channel: tecmath

Math Antics - Angles & Degrees

Published: 2013/09/10

Channel: mathantics

❤︎² Radians and Degrees (mathbff)

Published: 2014/07/02

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Measuring angles in degrees | Angles and intersecting lines | Geometry | Khan Academy

Published: 2011/09/21

Channel: Khan Academy

Home Remodeling Tips : How to Set an Angle with a Speed Square

Published: 2012/01/26

Channel: essortment

How do we Construct a 30 Degree Angle?

Published: 2014/12/20

Channel: Don't Memorise

How to Draw 220 degrees Reflex Angle

Published: 2016/10/28

Channel: Anil Kumar

To construct 20 degree angle

Published: 2016/02/12

Channel: Techno Mentals

Reference Angle for an Angle, Ex 1 (Using Degrees)

Published: 2010/11/14

Channel: patrickJMT

Quick Tip #1: Cut the Perfect 45 Degree Angle

Published: 2014/06/07

Channel: Mead McLean

How to Frame a 45 Degree Angle Wall

Published: 2016/04/20

Channel: Basement Finishing Man

How To Construct A 15 Degree Angle (With A Compass And No Protractor).

Published: 2014/09/17

Channel: maths3000

How to construct a 60 degree angle / How to construct an equilateral triangle

Published: 2012/01/05

Channel: maths520

How to Construct 10 degree angle easily

Published: 2016/10/26

Channel: Techno Mentals

Constructing an Angle of 75 degrees

Published: 2013/06/09

Channel: Antonija Horvatek

Perfect 45 degree angle - with a piece of paper. No mitre required!

Published: 2016/06/28

Channel: David Pride

Constructing a 22,5 degree angle

Published: 2017/02/24

Channel: Geoffrey Comins

Constructing an Angle of 90 degrees

Published: 2013/06/03

Channel: Antonija Horvatek

How to Construct 20 and 50 degree of angle

Published: 2017/04/02

Channel: galaxy coaching classes

75 degree angle.avi

Published: 2012/05/03

Channel: O.R. Anderson

Finding 45 Degree From A Right Angle Using A Compass - How To Draw / Bisect / Bisection

Published: 2013/04/24

Channel: Savvas Papasavva

How To Draw A 30 Degree Angle With A Compass And Ruler (No Protractor)

Published: 2013/09/26

Channel: maths3000

How To make 50 Degree Angle - With Compass

Published: 2017/03/30

Channel: Asjad Siddiqui

Learn 135 degree angle without protractor or angle tool

Published: 2017/09/03

Channel: Nalemitho Easy Drawing

How to construct 55 degree angle

Published: 2017/04/23

Channel: Geomatrix Guys

60 Degree angle cuts - by Matt C.

Published: 2015/02/09

Channel: RusticSupplyCo. LLC

Construct 45 degree angle - Corbettmaths

Published: 2013/04/05

Channel: corbettmaths

HOW TO CONSTRUCT 20 & 110 DEGREE ANGLE WITH COMPASS ONLY

Published: 2017/01/25

Channel: MANISH SHARAN

Drawing 105 degree angle without protractor or angle tool

Published: 2017/03/07

Channel: Nalemitho Easy Drawing

How to draw 60 degree angle with a ruler and compass

Published: 2011/11/28

Channel: mattam66

Construct a 60 angle

Published: 2008/11/01

Channel: Mark Kingsbury

Learn to draw 75 degree angle without protractor or angle tool

Published: 2017/03/06

Channel: Nalemitho Easy Drawing

Use the 360 Degree visual protractor (AngleViewer) to draw an angle

Published: 2008/08/08

Channel: marylustephens

Draw an Angle of 60 , 120 and 180 degree

Published: 2017/02/11

Channel: STUDY MATERIAL Channel

Draw an angle of 240 300 and 360 Degree

Published: 2016/12/12

Channel: STUDY MATERIAL Channel

How to Draw 40° degree Angle with compass And scale

Published: 2017/07/01

Channel: Qurious to some Furious

ANGLE CONSTRUCTIONS USING COMPASS - 75 DEGREES

Published: 2013/04/08

Channel: Jigar Mehta

Constructing an Angle of 120 degrees

Published: 2013/06/03

Channel: Antonija Horvatek

Learn to draw 45 degree angle without protractor or angle tool

Published: 2016/10/24

Channel: Nalemitho Easy Drawing

Bessey 90 Degree Angle Clamps - WS-6 / WS-3 / WS-3+2K

Published: 2015/07/06

Channel: Real Tool Reviews

Constructing an Angle of 30 degrees

Published: 2013/06/03

Channel: Antonija Horvatek

How to construct an angle of 150 and 210 degree

Published: 2016/12/13

Channel: STUDY MATERIAL Channel

Constructing an Angle of 45 degrees

Published: 2013/06/03

Channel: Antonija Horvatek

How To Cut a 45 Degree Angle On a Pipe

Published: 2013/10/13

Channel: kbbacon

How to use an angle degree torque gauge - Auto Information Series

Published: 2013/11/16

Channel: Robert DIY

Using a Circular Saw : Circular Saw 22 Degree Angle Cuts

Published: 2008/08/31

Channel: expertvillage

Controlling Balll With a 90 Degree Angle (Tangent Line)

Published: 2011/02/27

Channel: BrandonBilliardGuy

Constructing a 30 degree angle - Corbettmaths

Published: 2013/03/25

Channel: corbettmaths

How to cut a 15 degree angle on pipe | 30° Miter bend from pipe

Published: 2016/12/07

Channel: Technical Piping

Quickest way to draw 20 degree angle by compass

Published: 2016/11/13

Channel: RAVI GANGWAR

Degree | |
---|---|

Unit system | Non-SI accepted unit |

Unit of | Angle |

Symbol | °^{[1]}^{[2]} or deg^{[3]} |

Unit conversions | |

1 °^{[1]}^{[2]} in ... |
... is equal to ... |

turns | 1/360 turn |

radians | π/180 rad |

gons | 10/9^{g} |

A **degree** (in full, a **degree of arc**, **arc degree**, or **arcdegree**), usually denoted by **°** (the degree symbol), is a measurement of a plane angle, defined so that a full rotation is 360 degrees.

It is not an SI unit, as the SI unit of angular measure is the radian, but it is mentioned in the SI brochure as an accepted unit.^{[4]} Because a full rotation equals 2π radians, one degree is equivalent to π/180 radians.

The original motivation for choosing the degree as a unit of rotations and angles is unknown. One theory states that it is related to the fact that 360 is approximately the number of days in a year.^{[5]} Ancient astronomers noticed that the sun, which follows through the ecliptic path over the course of the year, seems to advance in its path by approximately one degree each day. Some ancient calendars, such as the Persian calendar, used 360 days for a year. The use of a calendar with 360 days may be related to the use of sexagesimal numbers.

Another theory is that the Babylonians subdivided the circle using the angle of an equilateral triangle as the basic unit and further subdivided the latter into 60 parts following their sexagesimal numeric system.^{[6]}^{[7]} The earliest trigonometry, used by the Babylonian astronomers and their Greek successors, was based on chords of a circle. A chord of length equal to the radius made a natural base quantity. One sixtieth of this, using their standard sexagesimal divisions, was a degree.

Aristarchus of Samos and Hipparchus seem to have been among the first Greek scientists to exploit Babylonian astronomical knowledge and techniques systematically.^{[8]}^{[9]} Timocharis, Aristarchus, Aristillus, Archimedes, and Hipparchus were the first Greeks known to divide the circle in 360 degrees of 60 arc minutes.^{[10]} Eratosthenes used a simpler sexagesimal system dividing a circle into 60 parts.

The division of the circle into 360 parts also occurred in ancient India, as evidenced in the Rigveda:^{[11]}

Twelve spokes, one wheel, navels three.

Who can comprehend this?

On it are placed together

three hundred and sixty like pegs.

They shake not in the least.— Dirghatamas, Rigveda 1.164.48

Another motivation for choosing the number 360 may have been that it is readily divisible: 360 has 24 divisors,^{[note 1]} making it one of only 7 numbers such that no number less than twice as much has more divisors (sequence A072938 in the OEIS).^{[12]}^{[13]} Furthermore, it is divisible by every number from 1 to 10 except 7.^{[note 2]} This property has many useful applications, such as dividing the world into 24 time zones, each of which is nominally 15° of longitude, to correlate with the established 24-hour day convention.

Finally, it may be the case that more than one of these factors has come into play. According to that theory, the number is approximately 365 because of the apparent movement of the sun against the celestial sphere and that it was rounded to 360 for some of the mathematical reasons cited above.

For many practical purposes, a degree is a small enough angle that whole degrees provide sufficient precision. When this is not the case, as in astronomy or for geographic coordinates (latitude and longitude), degree measurements may be written using decimal degrees, with the degree symbol behind the decimals; for example, 40.1875°.

Alternatively, the traditional sexagesimal unit subdivisions can be used. One degree is divided into 60 *minutes (of arc)*, and one minute into 60 *seconds (of arc)*. Use of degrees-minutes-seconds is also called DMS notation. These subdivisions, also called the *arcminute* and *arcsecond*, are respectively represented by a single and double prime. For example, 40.1875° = 40° 11′ 15″, or, using quotation mark characters, 40° 11' 15". Additional precision can be provided using decimals for the arcseconds component.

The older system of thirds, fourths, etc., which continues the sexagesimal unit subdivision, was used by al-Kashi and other ancient astronomers, but is rarely used today. These subdivisions were denoted^{[citation needed]} by writing the Roman numeral for the number of sixtieths in superscript: 1^{I} for a "prime" (minute of arc), 1^{II} for a second, 1^{III} for a third, 1^{IV} for a fourth, etc. Hence the modern symbols for the minute and second of arc, and the word "second" also refer to this system.^{[citation needed]}

In most mathematical work beyond practical geometry, angles are typically measured in radians rather than degrees. This is for a variety of reasons; for example, the trigonometric functions have simpler and more "natural" properties when their arguments are expressed in radians. These considerations outweigh the convenient divisibility of the number 360. One complete turn (360°) is equal to 2*π* radians, so 180° is equal to π radians, or equivalently, the degree is a mathematical constant: 1° = ^{π}⁄_{180}.

The turn (or revolution, full circle, full rotation, cycle) is used in technology and science. One turn is equal to 360°.

With the invention of the metric system, based on powers of ten, there was an attempt to replace degrees by decimal "degrees"^{[note 3]} called *grad* or *gon*, where the number in a right angle is equal to 100 gon with 400 gon in a full circle (1° = ^{10}⁄_{9} gon). Although that idea was abandoned by Napoleon, grades continued to be used in several fields and many scientific calculators support them. Decigrades ( ^{1}⁄_{4,000}) were used with French artillery sights in World War I.

An angular mil, which is most used in military applications, has at least three specific variants, ranging from ^{1}⁄_{6,400} to ^{1}⁄_{6,000}. It is approximately equal to one milliradian (c. ^{1}⁄_{6,283}). A mil measuring ^{1}⁄_{6,000} of a revolution originated in the imperial Russian army, where an equilateral chord was divided into tenths to give a circle of 600 units. This may be seen on a lining plane (an early device for aiming indirect fire artillery) dating from about 1900 in the St. Petersburg Museum of Artillery.

Turns | Radians | Degrees | Gradians (Gons) |
---|---|---|---|

0 | 0 | 0° | 0^{g} |

1/24 | π/12 | 15° | 16 2/3^{g} |

1/12 | π/6 | 30° | 33 1/3^{g} |

1/10 | π/5 | 36° | 40^{g} |

1/8 | π/4 | 45° | 50^{g} |

1/2π | 1 | c. 57.3° | c. 63.7^{g} |

1/6 | π/3 | 60° | 66 2/3^{g} |

1/5 | 2π/5 | 72° | 80^{g} |

1/4 | π/2 | 90° | 100^{g} |

1/3 | 2π/3 | 120° | 133 1/3^{g} |

2/5 | 4π/5 | 144° | 160^{g} |

1/2 | π | 180° | 200^{g} |

3/4 | 3π/2 | 270° | 300^{g} |

1 | 2π | 360° | 400^{g} |

- Compass
- Geographic coordinate system
- Gradian
- Meridian arc
- Square degree
- Square minute
- Square second
- Steradian

**^**The divisors of 360 are 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180, and 360.**^**Contrast this with the relatively unwieldy 2520, which is the least common multiple for every number from 1 to 10.**^**These new and decimal "degrees" must not be confused with decimal degrees.

**^***HP 48G Series – User's Guide (UG)*(8 ed.). Hewlett-Packard. December 1994 [1993]. HP 00048-90126, (00048-90104). Retrieved 2015-09-06.**^***HP 50g graphing calculator user's guide (UG)*(1 ed.). Hewlett-Packard. 2006-04-01. HP F2229AA-90006. Retrieved 2015-10-10.**^***HP Prime Graphing Calculator User Guide (UG)*(PDF) (1 ed.). Hewlett-Packard Development Company, L.P. October 2014. HP 788996-001. Retrieved 2015-10-13.**^**Bureau International des Poid et Mesures (2006). "The International System of Units (SI)" (8 ed.). Archived from the original on 2009-10-01.**^**"Degree". MathWorld.**^**Jeans, James Hopwood (1947).*The Growth of Physical Science*. p. 7.**^**Murnaghan, Francis Dominic (1946).*Analytic Geometry*. p. 2.**^**Rawlins, Dennis. "On Aristarchus".*DIO - The International Journal of Scientific History*.**^**Toomer, Gerald J.*Hipparchus and Babylonian astronomy*.**^**"2 (Footnote 24)".*Aristarchos Unbound: Ancient Vision / The Hellenistic Heliocentrists' Colossal Universe-Scale / Historians' Colossal Inversion of Great & Phony Ancients / History-of-Astronomy and the Moon in Retrograde!*(PDF).*DIO - The International Journal of Scientific History*.**14**. March 2008. p. 19. ISSN 1041-5440. Retrieved 2015-10-16.**^**Dirghatamas.*Rigveda*. pp. 1.164.48.**^**Brefeld, Werner. "Divisibility highly composite numbers".**^**Brefeld, Werner (2015).*(not defined)*. Rowohlt Verlag. pp.*Not yet published*.

Wikimedia Commons has media related to .Degree (angle) |

- "Degrees as an angle measure"., with interactive animation
- "Degree". at MathWorld
- Gray, Meghan; Merrifield, Michael; Moriarty, Philip (2009). "° Degree of Angle".
*Sixty Symbols*. Brady Haran for the University of Nottingham.

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