Acute Triangle: a triangle with no angle measuring 90 degrees or more.
Associative Property of Multiplication: the product stays the same when the grouping of factors is changed. (a x b) x c = a x (b x c), where a, b, and c stand for any real numbers.
Attribute: a characteristic.
Example: size, shape or color
Base of a Solid Figure: a base of a solid figure is usually thought of as a face upon which it can ¨sit.¨ Most solid figures have more than one base.
Congruent: having exactly the same size and shape.
Cube: a rectangular solid having 6 congruent square faces.
Cubic Unit: a unit such as a cubic meter to measure volume or capacity.
Decagon: a polygon with 10 sides.
Decagonal Prism: a prism whose two bases are decagons.
Diagonal: a line that goes through vertices of a polygon that are not next to each other.
Equiangular Triangle: a triangle with all equal angles (60 degrees).
Equilateral Triangle: a triangle with all sides the same length.
Formula: a general mathematical rule that is written as an equation.
Height: a perpendicular line segment from the base to the top of the figure.
Heptagon: a polygon with 7 sides.
Hexagon: a polygon with 6 sides.
Hexagonal Prism: a prism whose two bases are hexagons.
Hierarchy: an organizational chart to show classification or relationships based on properties.
Isosceles Triangle: a triangle that has exactly 2 equal sides.
Lateral Face: the face of a prism or pyramid that is not a base.
Line of Symmetry: a line that divides a figure into two congruent halves that are mirror images of each other.
Line Symmetry: what a figure has if it can be folded in half and its two parts match exactly.
Nonagon: a polygon with 9 sides.
Obtuse Triangle: a triangle that has an angle greater than 90 degrees (obtuse angle).
Octagon: a polygon with 8 sides.
Octagonal Prism: a prism whose two bases are octagons.
Parallel Lines: lines that are always the same distance apart. They do not intersect.
Parallelogram: a quadrilateral with 2 pairs of parallel and congruent sides.
Pentagon: a polygon with 5 sides.
Pentagonal Prism: a prism whose two bases are pentagons.
Pentagonal Pyramid: a pyramid that has a pentagonal base.
Perpendicular: forming right angles.
Perpendicular Lines: two lines that form right angles.
Polygon: a closed plane figure made by line segments.
Polyhedron: a three-dimensional figure in which all the faces are polygons. Polyhedrons have NO curved surfaces.
Prism: a three-dimensional figure that has two congruent and parallel faces that are polygons. The remaining faces are parallelograms.
Pyramid: a polyhedron whose base is a polygon and whose other faces are triangles that share a common vertex.
Quadrilateral: a polygon with 4 sides.
Rectangle: a quadrilateral with 2 pairs of congruent, parallel sides and 4 right angles.
Regular Polygon: a polygon with all sides the same length and all angles the same measure.
Rhombus: a quadrilateral with all 4 sides equal in length.
Right Rectangular Prism: a prism with 6 rectangular faces where the lateral edge is perpendicular to the plane of the base.
Right Triangle: a triangle that has one 90 degree angle.
Scalene Triangle: a triangle that has no equal sides.
Solid Figure: three-dimensional figure that has length, width, and height.
Square: a parallelogram with 4 equal angles AND 4 equal sides.
Three-Dimensional Figure: a solid figure that has length, width, and height.
Trapezoid: a quadrilateral with one pair of parallel sides and one pair of sides that are not parallel.
Two-Dimensional Figure: a plane, flat figure that has length and width.
Unit Cube: a precisely fixed quantity used to measure volume.
Variable: a letter or symbol that represents a number.
Volume: the number of cubic units it takes to fill a figure.
