To find the area or perimeter, it is not obligatory to possess big knowledge of geometry. There are ways to do it and without calculations, but the methods demanding knowledge of formulas and abilities to use them, are most exact.
Instruction
1. If you have a figure of any area which requires to define area and perimeter, and you cannot use usual formulas for calculations as it is not a rectangle, a circle or a trapeze, and something is more difficult on a configuration, first of all, divide this figure into parts. Usually polygons divide into triangles if your set figure has curved lines in perimeter, allocate triangles and segments of a circle. Complete segments to a cycle to have an opportunity to measure the necessary values. Having divided all figures into similar elements, count the area for each of them. The area of a triangle equals to a half of a prozvedeniye of one of its parties on height lowered to this party. Measure by a ruler for each triangle the necessary lengths, substitute values in a formula and count the area of each triangle. If you allocated except triangles as elements, and circle segments, consider their area on a formula π^2*а/360-S where an is the central corner which two radiuses are connected among themselves by a segment arch; S – the area of the triangle formed by the same radiuses and a straight line which can straighten an arch, having connected radiuses. When all areas of separate elements are known to you summarize them to find out the area of the necessary figure.
2. To learn perimeter, it is necessary to measure all rectilinear pieces in it and to put them. Then to add to the received number, the calculated lengths of arches. Length of an arch of a circle is calculated as the work of radius of a circle on a corner and, already mentioned above.
3. It is possible to be limited to a minimum of calculations if to use other methods for determination of the area. So you can use a palette. Impose a palette over a figure for which you determine the area, count all units of area blocking the required area, and then increase the received number by the known area of unit of measure of a palette.
4. The weight method of determination of the area demands more tools. If you have exact scales, copy the image of the required square at a leaf of the known format, weigh it. Now cut out the image of a figure and measure its weight. When the area and weight of the whole leaf and also weight of its part is known to you, it is possible to make a proportion and to determine the area of this part. It is better to use this method if paper of manufacturing.
5. And the easiest way to measure perimeter, to lay thread on all line of perimeter. It is important that thread precisely coincided with perimeter. When thread becomes isolated, that is will take a cycle in the area of perimeter, note a point on it in which the thread adjoined to the place of a reference mark. Cut off and measure the received length, the value of your measurement is and there is a perimeter of this figure.