Often you have to work with geometricfigures, calculations which can not be easily explained. If you want to find the area of a square or a rectangle, they can be divided into some parts and intuitively derive the correct formula. However, the circumference is not quite a standard object for ordinary schoolchildren. Often there is a misunderstanding of this topic. Let's see what's wrong.
The circle itself is formed due to two parameters:radius and geometric position of the center. The latter understands high school, so he is of little interest to us. But the first sets the basic properties, such as area. The length of the circle actually depends only on the radius and is calculated using the following formula:
L = 2PR
За искомый показатель принимаем L.The multiplier П ("Пи") is a constant. To successfully solve problems at school, it is enough to know that = 3.14. However, it is not always necessary to substitute this value, since it is very simplified. If we are talking about large scales, then it is necessary to take into account a considerable number of decimal places. Therefore, in many cases, a more acceptable answer is in general form without any rounding. Remember that the calculation of the circumference depends only on the radius. This is an indicator of how far all points of the circle are from the center. Accordingly, the larger this parameter, the longer the arc. Like conventional distance readings, L is measured in meters. P is the radius.
In more realistic conditions there are complicatedtasks. For example, when the length of the arc of a circle. Here the formula is a bit more complicated. It should be understood that it is based on the basic pattern, but cuts off part of length that you do not need. In general terms, it can be written as:
L = 2PR / 360 * n
As you can see, there is one new variable n.This is a visual designation. The entire circumference was divided into 360 degrees. Thus, it became known how many meters fall on 1 degree. Further, substituting the values of the required turnover around the axis instead of the letter n, we get the long-awaited answer. Taking a single segment, we proportionally increased it n times.
Why in real life you need to know what is equal tocircumference? This question can not be answered that would cover all applications. But for acquaintance we will begin with primitive hours. Knowing the radius of motion of the second hand, you can find the distance that it should go in a minute. Once the path and time become known, we can find the speed with which it moves. And then only those involved in hours will go deeper. If a cyclist moves on a circular track, his travel time depends on the speed and radius. You can find and accelerate it. In washing machines, it also does not do without an indicator, which we almost dismantled. There the circumference is necessary for counting the revolutions (everything depends on the distance), done for a certain amount of time. In more large-scale conditions, due to the circumference, the motion of the planets in orbits is predicted, and so on.
Thus, for a clear understanding of the topic, you need to remember only two formulas. This knowledge will be useful to you not only in school for good grades, but also in real life.
