The radian is the SI unit for measuring angles, is the standard unit of angular measure used in many areas of mathematics. The length of an arc of a unit circle is numerically equal to the measurement in radians of the angle that it subtends; the unit was an SI supplementary unit, but this category was abolished in 1995 and the radian is now considered an SI derived unit. The symbol rad can be used to represent the radian, but this is omitted in mathematical writing. Radian describes the plane angle subtended by a circular arc as the length of the arc divided by the radius of the arc. One radian is the angle subtended at the center of a circle by an arc, equal in length to the radius of the circle. More the magnitude in radians of such a subtended angle is equal to the ratio of the arc length to the radius of the circle. Conversely, the length of the enclosed arc is equal to the radius multiplied by the magnitude of the angle in radians; as the ratio of two lengths, the radian is a "pure number" that needs no unit symbol, in mathematical writing the symbol "rad" is always omitted.

When quantifying an angle in the absence of any symbol, radians are assumed, when degrees are meant the symbol ° is used. The radian is defined as 1, it follows that the magnitude in radians of one complete revolution is the length of the entire circumference divided by the radius, or 2πr / r, or 2π. Thus 2π radians is equal to 360 degrees, meaning; the relation 2 π rad = 360 ∘ can be derived using the formula for arc length. Taking the formula for arc length, or ℓ a r c = 2 π r. Assuming a unit circle. Knowing that the definition of radian is the measure of an angle that subtends an arc of a length equal to the radius of the circle, we know that 1 = 2 π; this can be further simplified to 1 = 2 π rad 360 ∘. Multiplying both sides by 360 ∘ gives 360 ∘ = 2 π rad; the concept of radian measure, as opposed to the degree of an angle, is credited to Roger Cotes in 1714. He described the radian in everything but name, he recognized its naturalness as a unit of angular measure. Prior to the term radian becoming widespread, the unit was called circular measure of an angle.

The idea of measuring angles by the length of the arc was in use by other mathematicians. For example, al-Kashi used so-called diameter parts as units where one diameter part was 1/60 radian and they used sexagesimal subunits of the diameter part; the term radian first appeared in print on 5 June 1873, in examination questions set by James Thomson at Queen's College, Belfast. He had used the term as early as 1871, while in 1869, Thomas Muir of the University of St Andrews, vacillated between the terms rad and radian. In 1874, after a consultation with James Thomson, Muir adopted radian; the name radian was not universally adopted for some time after this. Longmans' School Trigonometry still called the radian circular measure when published in 1890; the International Bureau of Weights and Measures and International Organization for Standardization specify rad as the symbol for the radian. Alternative symbols used 100 years ago are c, the letter r, or a superscript R, but these variants are infrequently used as they may be mistaken for a degree symbol or a radius.

So, for example, a value of 1.2 radians would most be written as 1.2 rad. As stated, one radian is equal to 180/π degrees. Thus, to convert from radians to degrees, multiply by 180/π. Angle in degrees = angle in radians ⋅ 180 ∘ π For example: 1 rad = 1 ⋅ 180 ∘ π ≈ 57.2958 ∘ 2.5 rad = 2.5 ⋅ 180 ∘ π ≈ 143.2394 ∘ π 3 rad = π 3 ⋅ 180 ∘ π = 60 ∘ Conversely


Cheqbook is a cloud accounting Software-As-A-Service for small-to-medium business. Cheqbook automates downloading and categorizing transactions as well as offering invoicing, bill pay, reporting; the software is available via] monthly subscription on Mac, PC, tablet computers running a modern web browser. Subscriptions are tiered based on the number of books being managed. Accountants and bus iness ownerse[* can sharel their books. Cheqbook was founded with a $651,000 seed round raised on December 31, 2010. CEO Doug Levin's CPA firm Levin & Hu CPAs was unable to recommend cloud based solutions and still recommended the desktop version of Quickbooks. Cheqbook was founded with the purpose of building that software that CPAs needed while being intuitive for business owners. Private beta began on April 23, 2012. Cheqbook launched on May 17, 2013; the Pro marketplace for accountants and bookkeepers was launched on July 10, 2013. Cheqbook is cloud accounting software for small-to-medium business. Cheqbook primary focus is being intuitive for new business owners while having the flexibility and pro features that CPAs need.

Features include: Bank synchronization, Automatic categorization, Bills, Check Printing, Bank reconciliation, The Pro Marketplace is free match-making service that pairs business owners with accountants and bookkeepers in their community. General Official Site


The artsdepot is a multi-purpose cultural centre located in North Finchley, in the London borough of Barnet. It was opened on 23 October 2004 for the enjoyment and development of the arts in North London; the venue comprises two main theatre spaces, The Pentland Theatre with 395 seats and a Studio Theatre with 148 seats. The building contains dance and drama studios, a gallery space and a cafe; the programme of performances ranges from theatre, to live music, dance, visual art, spoken word and children's events. Artsdepot runs a programme of an educational courses for children and adults. Outreach programmes include working with local schools, artistic companies, other venues, festivals; the artsdepot was conceived in 1996 at the Barnet 2000 conference, which addressed what new and improved services the borough's residents would like to see in Barnet at the new Millennium. What emerged from Barnet 2000 was a need for more professional arts facilities to supplement the facilities at the existing Bull Arts Centre in High Barnet, at that time the only professional, if small, arts centre in the borough.

Barnet Council officers worked on the feasibility of using the Tally Ho site and brought together partners including Old Bull Arts Centre, Barnet College and Community Focus. After a capital lottery bid failed, The London Borough of Barnet sought a commercial developer to work with, they contracted ACT theatre consultants to design the theatre spaces. The developers contracted architects Ruddle Wilkinson; the design was a result of close working with the main partners and the artistic vision was developed by The Bull Arts Centre's director, Alison Duthie. The developers Taylor Woodrow developed plans for the Tally Ho regeneration in which artsdepot is located; the people of North London gained a state-of-the-art arts centre with most of the construction costs coming from the commercial development. The site on which artsdepot was built had been empty, apart from a weekly market, relocated to the nearby Lodge Lane car park, for over 20 years since the Gaumont cinema closed down in 1980. In December 2001, the project was launched with the name "artsdepot" by the Secretary of State for Culture and Sport, Tessa Jowell, when the building works began.

The venue was opened to the public for the first time on Saturday 23 October 2004 receiving over 2,500 visitors for its Community Open Day. The building was opened on 26 November 2004 by The Earl of Wessex. Official website