Geometry Angie Bordwell, Vertis Lewis, Lissa Purpura, and Jean Tuquero

What is Geometry? Geometry is the study of the measurement, properties, and relationships of points, lines, angles, surfaces, and solids.

Polygons Polygons are closed figures made by joining line segments, where each line segment intersects exactly two others.

Triangles Triangles are 3 sided polygons or shapes and are classified classify triangles according to length of sides and measurement of the angles.

Triangles by sides Equilateral Triangles have 3 equal sides. Isosceles Triangles have 2 equal sides. Scalene Triangle have NO equal sides.

Triangles by angles Acute Triangle are triangles with three acute angles. Right Triangle are triangles with one right angle. Obtuse Triangle are triangles with one obtuse angle.

Quadrilateral Quadrilaterals are 4 sided polygons or shapes.

Quadrilateral Some examples are Rectangles are four-sided polygon having all right angles. Squares are four-sided polygon having equal- length sides meeting at right angles. Parallelograms are four-sided polygon with two pairs of parallel sides.

Quadrilateral Rhombus is a four-sided polygon having all four sides of equal length. Trapezoids are four-sided polygons having exactly one pair of parallel sides.

Plane figure having five sides and five angles. In geometry, a pentagon is any five- sided polygon (figure with many sides or angles). However, the term is commonly used to mean a regular pentagon, where all sides are equal and all angles are equal (to 108°). Pentagon

Heptagon A polygon (figure with many sides or angles) having seven sides. A heptagon is a plane figure with seven sides and seven angles. In a regular heptagon, in which all sides and all angles are equal, the sides meet at an angle of approximately degrees.

Octagon An octagon is a polygon that has eight sides. The internal angle at each vertex of a regular octagon is 135°.°

Angles Acute - an angle whose measure is between 0 o and 90 o Right - An angle whose measures 90°, one-quarter of the full circle. Obtuse - an angle whose measure is between 90 o and 180 o Supplementary - two angles whose measures total 180 o. Complementary- two angles whose measures total 90 o.

Figures Similar- figures that have the same shape but not necessarily the same size.  Congruent - figures that have the same size and same shape.

Lines Line of Symmetry - a line that divides a figure into two parts, each a mirror image of the other. Parallel Lines – continuous at equal distance corresponding, exactly like each other. Perpendicular Lines- two segments or lines that intersect to form right angles.

Coordinate Planes a plane that is divided into four quadrants by drawing a vertical and a horizontal line that intersect at a point called the origin.

Reflection (Coordinate Plane) Reflection - a transformation of a geometric figure that results in a mirror image of it. The object and the image are equal distance from the line of reflection.

Translation (Coordinate Plane) Translation - An exact duplication of a geometric figure formed by moving each point in the figure the same distance and in the same direction.

Rotation (Coordinate Plane) A transformation of a figure in which the image is formed by turning the figure about a fixed point called the center of rotation which may be inside or outside the figure.