Step 2 Unit 5 Key Terms

  • 2-Dimensional: A shape that only has two dimensions (such as width and height) and no thickness.
  • 3-Dimensional: An object that has height, width and depth (thickness), like any object in the real world.
  • Area: The number of square units it takes to completely fill a space or surface.
  • Bases of a Prism: The two faces formed by congruent polygons that lie in parallel planes, all of the other faces being parallelograms.
  • Cubic Units: Volume of the solids is measured in Cubic Units.
  • Edge: The intersection of a pair of faces in a three-dimensional figure.
  • Equilateral Triangle: A triangle which has all three of its sides equal in length.
  • Face: One of the polygons that makes up a polyhedron.
  • Fractional edge length: The length of each edge of the cube is a fraction.
  • Isosceles Triangle: A triangle which has two of its sides equal in length.
  • Kite: A quadrilateral with two distinct pairs of equal adjacent sides. A kite-shaped figure.
  • Lateral Faces:   In a prism, a face that is not a base of the figure.
  • Net: A two-dimensional figure that, when folded, forms the surfaces of a three- dimensional object.
  • Parallelogram: A quadrilateral with both pairs of opposite sides parallel.
  • Polygon: A number of coplanar line segments, each connected end to end to form a closed shape.   A regular polygon has all sides equal and all interior angles equal.   An irregular polygon sides are not all the same length nor does the interior angles have the same measure.
  • Polyhedron: A 3-dimensional figure that has polygons as faces.
  • Prism: A polyhedron with two parallel and congruent faces, called bases, and all other faces that are parallelograms.
  • Quadrilaterals: Four coplanar line segments linked end to end to create a closed figure. A 4-sided polygon.
  • Rectangle:   A 4-sided polygon where all interior angles are 90°.
  • Rectangular prism: A solid (3-dimensional) object which has six faces that are rectangles.
  • Rhombus: A quadrilateral with all four sides equal in length.
  • Right Triangle: A triangle where one of its interior angles is a right angle (90 degrees).
  • Right rectangular prism:   In a right prism, the lateral faces are each perpendicular to the bases.
  • Scalene Triangle: A triangle where all three sides are different in length.
  • Square: A quadrilateral that has four right angles and four equal sides.
  • Surface area: The total area of the 2-dimensional surfaces that make up a 3-dimensional object.
  • Trapezoid: A quadrilateral which has one pair of parallel sides.
  • Triangles: A closed figure consisting of three line segments linked end-to-end. A 3-sided polygon
  • Triangular prism: A prism whose bases are triangles.   A solid (3-dimensional object what has five faces: three rectangles and two bases.)
  • Vertices: The common endpoint of two or more rays or line segments
  • Volume: The amount of space occupied by an object.

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