Every day we meet polygons. Even the plan of the apartment or garden site consists of polygons. To calculate necessary quantity of boards on construction of a fence or how many rolls of wall-paper it is necessary on pasting of walls in the apartment, always at first measure perimeter of a polygonal figure. Perimeter of a polygon call the sum of lengths of its parties. Depending on type of a polygon and devices for measurement of length the ways of finding of perimeter of a figure can be various.
It is required to you
- - ruler
- - thread
- - scissors
Instruction
1. If the measured regular polygon, that is at it all parties and corners are equal, then for finding of perimeter measure length of one of its parties by means of a ruler. Then count quantity of corners of a polygon which is equal the number of its parties. Increase the turned-out number by length of the party of a figure. It will be polygon perimeter.
2. If the polygon symmetric also has 2 or 4 couples of equal set of the parties, then measure at first length of the parties on one of the repeating sites. Then put the received values and for receiving perimeter of a figure increase this sum by quantity of the repeating parts in a polygon.
3. To find square perimeter, measure one of the parties and increase the received value by four. If before you a pentagon, then on four; if a hexagon, then on six.
4. For calculation of perimeter of a polygon at which all parties have different length measure by a ruler each of the parties. Then, having put the received numbers, you receive polygon perimeter.
5. If you do not want to correlate every time at measurement of the parties length reference point on a ruler or a roulette to a polygon corner, then lay a usual rope on a figure edge. In that place where the measuring instrument, having bypassed the parties of a figure, will concern the tip, cut off it scissors. Length of measuring thread will be equal to perimeter of a polygonal figure. For finding of numerical value of perimeter just measure rope length by means of a ruler or a roulette.
6. When finding perimeter of a difficult polygon which can be broken into several different polygons at first find lengths of the parties of each of figures which form a difficult contour, and then put the turned-out numbers. Such way is good if the difficult figure consists of regular polygons which it is easier to count perimeter, than figures with different lengths of the parties.