The word chord has several values. Everyone is familiar with the Word, from school textbooks, as a mathematical and biological term. In some cases, the name "chord" is known only to a narrow circle of specialists. Consider where and when the word "chord" is used.
Chord in geometry
Chord in geometry is a segment connecting two points on the circle.
To build chords you need:
- draw a circle
- mark two points on it
- connect their straight line
Chord, leaving the perimeter of the circle, is called the Sale.
The geometric figure between the chord and the circle is called the segment, and the arc of the circle between the two points is called an arc. The greatest chord is a diameter, it connects two points on the circle and passes through the center. Two chords emerging from one point on the circle form an enclosed angle, and the diameter is deployed.
In planimetry The chord is a securing segment passing through the line curve and crossing it at several points. It may not only be a circle, but also ellipse, hyperbole, parabola. The properties of chord and the sequential use in urban planning. To connect two districts or areas reduce the distance and build roads, connecting the chord or sequer curve.
Horde properties are used in the aircraft industry. There is a term "chord line" - a segment connecting the most remote wing profile points. When designing aircraft, the average aerodynamic chord of the profile is taken into account.
Chord in zoology
Representatives of fauna with axial skeleton - chord are combined into a general type of chord. The lower representative is an elastic litigation, which in the process of evolution, from the highest representatives of the animal world, acquires the perfect form - the spine. The simplest chords remains for life. At the highest chord, elastic litter is present in the germinal stage or persisted in part in the skeleton.
In the school program, chord is studied by the example of a primitive representative of the chordant - Lanctress.
The spinal litter for the simplest animal is support for internal organs, participates in the process of movement along with primitive muscles. Over the chord of the lancing is a nervous tube, from its front department at the highest organisms, a brain is formed, from the rear spinal department. From the chord itself, a spine is formed segmented by vertebrae and departments that perform a specific function. Animals whose chord has been preserved for life - this is a lancing board and representatives of some fish detachments:
- headhead
- dipnoi
- cartilage
- sturgeon
Chord in the heart
The human heart consists of four cameras: two ventricles and two atrium. Blood is pushed out of the atrium in the ventricle, which has a valve and opens through the tension of chord-muscular heavy. Then the chords relax and prevent the reverse move of blood. The ultrasound is determined by the chord anomaly:
- thickening
- attach only on one side of the ventricle
- extra or transverse chords are formed
Such patients must be under the supervision of a doctor - cardiologist.
Chord in sociology
Animals having chord the most primitive from a large number of chordovy representatives. In sociology, the term "chord" is used to explain the simplest public organization borrowed from the animal world. Members of the Society unites a common goal, and the task is to distribute all benefit products. In this public, there is no hierarchy, all are equal.
If you search for encyclopedia, you can find the Spanish surname of the chord, the German soup - chord with prunes (like Soup - Harcho) and even the name of the "chord" of the Moscow Metro's highway. Sports weapon - onions has a the tutor, which is often called chord. One word has several values \u200b\u200bthat are not always connected with each other in meaning.
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