Download Geometry Study Guide - Demarest School District

POLYGONS:
Polygons:
a closed figure
formed by three or more line segments
lines do not cross
no curved lines
A polygon is named by the number of its sides or by the number of its angles.
Triangle - 3 sided
Pentagon - 5 sided
Heptagon - 7 sided
Nonagon - 9 sided
Dodecagon - 12 sided
Quadrilateral - 4 sided
Hexagon - 6 sided
Octagon - 8 sided
Decagon - 10 sided
Congruent: Same Measure
Regular Polygon: a polygon where all sides are congruent and all angles are congruent
TRIANGLES:
Triangles can be classified by their angle measures: EVERY triangle has 2 acute angles: you classify a
triangle using its third angle.
Acute Triangles / Obtuse Triangles / Right Triangles
Triangles can also be classified by the number of congruent sides they have:
Equilateral Triangle: all sides are equal
Scalene Triangle: All different sides
QUADRILATERALS:
Quadrilateral: a 4-sided polygon
Square: parallelogram, 4 right angles, 4 congruent sides
Rectangle: parallelogram, 4 right angles
Parallelogram: opposite sides are parallel and congruent
Rhombus: parallelogram, 4 congruent sides
Trapezoid: exactly one pair of opposite sides parallel
Isosceles Triangle: two equal sides
3-D FIGURES:
Prism: a figure that has two congruent polygons as bases
Pyramid: a figure with only one base
BOTH Prisms and Pyramids are named after the shape of its base.
Cone: has one circular base and one curved surface
Cylinder: has two congruent circular bases and 1 curved surface
Sphere: has no bases and 1 curved surface
Base: The bases of a prism are the two parallel congruent faces.
Face: Any surface that forms a side or a base of a prism. (FLAT)
Edge: The intersection of faces of a 3-D figure.
Vertex: the point where all the faces intersect (Corners)
VOLUME:
Volume of a solid figure is the measure of the space occupied by it. It is measured in cubic units.
Rectangular Prisms: a solid figure that has three sets of parallel congruent sides shapes like
rectangles.
V=lxwxh
(length x width x height)