Prisms and Cylinders

Prisms

  • A prism consists of a polygon on the bottom and a congruent polygon on the top, with all corresponding parts connected.
  • Examples:
    • Triangular prism: Triangle on the top, triangle on the bottom, with corresponding points connected.
    • Rectangular prism (box): Rectangle on the bottom, congruent rectangle on the top, with corresponding vertices connected.
  • The bottom and top are always congruent.

Right Prisms vs. Oblique Prisms

  • Right prisms: Have right angles.
    • Examples: Right triangular prism, right rectangular prism.
  • Oblique prisms: The top polygon is shifted or slanted relative to the bottom polygon.
    • Example: A square base with the top square moved over.
    • Oblique: A fancy word for slanted.

Volume of Prisms

  • The volume represents how much water (in cubic inches or cubic centimeters) it would take to fill the prism.
  • To find the volume: Find the area of the base and multiply by the height.
    • Volume=Area of BaseHeightVolume = Area \ of \ Base * Height
  • Units of measure: Cubic inches (a cube that is one inch wide, one inch long, and one inch high).
  • Height: The distance perpendicular to the base.
    • For oblique prisms, the height is not the slanted distance but the perpendicular distance to the base.

Cylinders

  • A cylinder is similar to a prism, but the base and top are circles.
  • The volume of a cylinder is found by taking the area of the base (circle) and multiplying by the height.
    • Volume=Area of BaseHeightVolume = Area \ of \ Base * Height
  • Right Cylinder: The height goes straight up perpendicular to the base.
  • Oblique Cylinder: Similar to an oblique prism.

Summary

  • Prisms and cylinders have easily calculated volumes.
  • To find the volume: Determine the area of the base, then multiply by the height, regardless of whether it's a prism or cylinder, right or oblique.