The perimeter is a total length of the parties of a geometrical figure. But if there is a need to quickly calculate perimeter something (for example, during repair or construction), not everyone will be able to make it with ease. Let's remember the basic rules for calculation of perimeter.
It is required to you
- geometriyesky figure, ruler, handle
Instruction
1. The perimeter for squares and rhombuses is calculated by formula P =4a where and is the length of one party of a figure. As all its parties are equal, measure one party and the received number increase by the number of the parties, i.e. by four.
2. For rectangles and parallelograms since at them not all parties but only opposite, there is other formula are equal: É = (and +b). Under and and b are meant the adjacent parties. Increase their total length by two.
3. To receive perimeter of a trapeze summarize lengths of all its parties (at a trapeze they are not identical), i.e. in this case use a formula P= and +b+ with +d.
4. The general formula for calculation of perimeter of a triangle looks as P = and +b+ with, i.e. you will have to put lengths of the parties of a triangle. But as triangles happen different types, calculations can be made differently. For example, if you know that the measured triangle – equilateral, then increase length of its party by three.
5. It is more difficult to calculate circle perimeter (circle length, p). It is known that length of a circle is 317 from length of diameter of a circle (d). In mathematics this ratio can be designated by the letter Pi (?) and to consider on the average as 3.14. It turns out what pd=?. From there is p=? d=2? r where r is a radius of the available circle. Therefore to calculate circle perimeter, you need to find at first circle radius, and then to increase this number by 2 and on 3.14.
6. If you had a need to learn arch perimeter, then for a start you need to measure two sizes – length of radius of an arch and central, i.e. formed by two radiuses (in degrees, n). Substitute the received sizes in p= Prn180 formula °.