Prism call the volume geometrical figure having two identical in a form the reasons and a number of side sides. Total number of sides of such figure is defined by a form of the polygon lying in its bases. Rectangular (it is more correct to speak "straight line") call a prism, each of side edges of which is perpendicular to both bases.
Instruction
1. You recognize that the volume of a direct prism is multiplication of the area of its basis by height. If any of these parameters, necessary for calculations, it is not set in an explicit form in basic data, then try to calculate it on other values given in statements of the problem.
2. For example, if in initial conditions there are no data on prism height, but lengths of diagonal of a side side and length of its the edge, general with the basis, are given, then use Pythagorean theorem. Diagonal, an edge of the known length and required height form a rectangular triangle in which you need to calculate one of legs on the known lengths of a hypotenuse and other leg. Take a square root from the difference between a square of length of diagonal and the second degree of length of the known edge. In the similar way it is possible to calculate height and according to other indirect data - for example, on lengths of diagonals of a side side and the angle of their crossing.
3. Calculate the area of the basis of a direct prism, using the formulas corresponding to its form. For example, if in the basis the correct triangle which length of an edge (a) is given in initial conditions lies, then you find the area of the basis multiplication of the squared length by private from division of a root from the three on the four: a² * √ 3/4. For more difficult polygonal bases use a formula in which length of the party (a) is squared, then is multiplied by the number of the parties (n) and a cotangent from number of Pi divided into this quantity and then decreases four times: ¼*a²*ctg(π/n). If the polygon lying in the prism basis is not the correct figure, then it is possible that it should be broken into several independent polygons, to calculate the area of everyone and to put the received results.
4. Increase the area of the basis of a direct prism calculated on the previous step by height received earlier - result of this operation and there will be a required volume of a figure.