The prism is a polyhedron which basis equal polygons, side sides — parallelograms form. To find prism cross-sectional area, it is necessary to know what section is considered in a task. Distinguish perpendicular and diagonal section.
Instruction
1. The way of calculation of cross-sectional area also depends on data which are already available in a task. Besides, the decision is defined by what lies in the prism basis. If it is necessary to find the diagonal section of a prism, find length of diagonal which is equal to a root from the sum (foundations of the parties in a square). For example, if the bases parties of a rectangleof are equal of 3 cm and 4 cm, respectively, length of diagonal is equal to a root from (4х4+3х3) = 5 cm. Find the area of diagonal section on a formula: diagonal of the basis to increase by height.
2. If in the basis of a prism there is a triangle, for calculation of cross-sectional area of a prism use a formula: 1/2 part of the basis of a triangle to increase by height.
3. In case in the basis there is a circle, find the cross-sectional area of a prism multiplication of number "пи" on the radius of the set figure in a square.
4. Distinguish the following types of prisms — correct and direct. If it is necessary to find the section of the correct prism, you need to know length only of one of the parties of a polygon, in the basis the square at which all parties are equal lies. Find the square diagonal which is equal to the work of its party on a root from two. After that having multiplied the diagonal and height, you receive the cross-sectional area of the correct prism.
5. The prism has the properties. So, the area of a side surface of any prism is calculated on a formula where — perimeter of perpendicular section — length of a side edge. At the same time perpendicular section is perpendicular to all side edges of a prism, and its corners are linear corners of dihedral angles at the corresponding side edges. Perpendicular section is perpendicular also to all side sides.