How to find perimeter if the area and width is known

How to find perimeter if the area and width is known

The perimeter is the sum of all parties of a polygon. If several parties of a polygon have the identical size, summation at calculation of perimeter can be combined with multiplication for calculation acceleration. Ready formulas of finding of perimeter are applied to regular polygons.


1. To calculate perimeter at the set areas and width of a polygon, it is necessary to know to know polygon type. The "length" and "width" parameters are usually applied to characteristic of a rectangle. A rectangle is called the quadrangle with right angles and in pairs equal parties.

2. Determine rectangle length. For this purpose divide the square at width set in a condition.

3. Calculate perimeter of a rectangle on a formula P=2L+2S where P — required perimeter; S — width set in a condition; L — length calculated in item 2.

4. A special case of a rectangle — a square. All four parties of a square are equal. Therefore for calculation of perimeter it is enough to know the size of one party. Calculate square perimeter on a formula P=4S where P — required perimeter; S — width set in a condition.

5. A parallelogram - too a regular polygon. The parties in it are in pairs equal and parallel. It is impossible to calculate the size of the party of a parallelogram on the known area and other party. It is necessary to know a corner between the parties of a parallelogram. The set conditions are not enough for calculation of perimeter of a parallelogram.

6. Draw any parallelogram. On the party with a size, known for a condition, lower height from parallelogram top. With the set width and the area parallelogram height — size invariable is also equal private from division of the square at width. The corner between the parties of a parallelogram on a condition is not set. At change of a corner the size of the unknown party of a parallelogram will change. Thus the task has a set of decisions.

Author: «MirrorInfo» Dream Team