Each corner has the-degree size. It is known to school students from elementary grades. But soon in the training program there is a concept of a-degree measure of an arch, and new tasks demand ability correctly it to calculate.
Instruction
1. The arch is the part of a circle concluded between two points lying on this circle. Any arch can be expressed through numerical values. Its main characteristic on an equal basis with long is the value of a-degree measure.
2. The-degree measure of an arch of a circle, as well as a corner, is measured in degrees which 360, or in minutes which in turn are divided into 60 seconds. On the letter the arch is designated by a badge which reminds the lower part of a circle and letters: two header (AV) or one lower case (a).
3. But at allocation on a circle of one arch another is involuntarily formed. Therefore unambiguously to understand about what arch it is, note one more point on the chosen arch, for example, S. Togda designation will take AVS form.
4. The piece which is formed by two points limiting an arch is a chord.
5. The-degree measure of an arch can be found through value of the entered corner which, having a top point on the circle, leans on this arch. Such corner is called entered in mathematics, and its-degree measure is equal to a half of an arch on which it leans.
6. Also in a circle there is the central corner. It also rests on a required arch, and its top is not on a circle any more, and in the center. And its numerical value is equal not to a half of a-degree measure of an arch, but its whole value any more.
7. Having understood as the arch through the corner leaning on it is calculated, it is possible to apply this law in the opposite direction and to output the rule that the entered angle which relies on diameter is right. As diameter divides a circle into two equal parts, so any of arches matters in 180 degrees. Therefore, the entered corner is equal 90 degrees.
8. Also, proceeding from a way of search of-degree value of an arch, ruled fairly that the corners leaning on one arch have equal value.
9. The value of a-degree measure of an arch is often applied to calculation of length of a circle or the arch. For this purpose use formula L = π*R*α/180.