Point

a location in space that has no size

Line

series of points that extends in opposite directions without end

Plane

flat serface with many lines and extends without end in many directions

Segment

part of a line with 2 end points

Ray

part of line with one end point

Parallel Lines

lines in the same plane that never intersect

Skew Lines

lines that lie in different planes they are neither parallel or intersecting

Adjacent Angles

two angles that share a common vertex and side, but have no common interior points

Vertical Angles

A pair of opposite congruent angles formed by intersecting lines

Congruent Angles

Angles that have the same measure

Supplementary Angles

Two angles whose sum is 180 degrees

Complementary Angles

Two angles whose sum is 90 degrees

Transversal

a line that intersects two or more lines in a plane at different points

Corresponding Angles

lie on the same side of the transversal and in corresponding positions

Alternate interior Angles

angles between 2 lines and on opposite sides of a transversal

Polygon

a closed plane figure formed by three or more line segments

Regular polygon

a polygon with all sides and all angles Congruent

Congruent Figures

Two figures that have the same shape and size the coresponding sides and angles are congruent

Circle

set of all points in a plane that are the same distance from a given point

Central Angle

an angle whose vertex is the center of the circle

Perpendicular lines

two lines that intersect to form right angles

Segment Bisector

a segment, ray, line, or plane that intersects a segment at its midpoint

Angle Bisector

a ray that divides an angle into two congruent angles

Translation

a transformation that moves points the same distance and in the same direction

Image

The figure after transformation

Reflectional symmetry

when one half is a mirror image of the other half

Line of symmetry

Divides a figure with reflectional symmetry into two congruent halves

Reflection

Transformation that flips a figure over

Line of reflection

reflected figure or image is congruent to original figure

Rotation

Transformation that turns a figure around a fixed point called Center of Rotation.

Center of Rotation

Fixed point

Rotational symmetry

You can rotate it 180 degrees or less

Acute triangle

3 acute angles

Right triangle

1 right angle

Obtuse triangle

1 obtuse angle

Equilateral triangle

3 congruent sides

Isosceles triangle

2 congruent sides

Scalene triangle

No congruent sides

Quadrilateral

4 sides

Square

4 90 degree angles and 4 congruent sides

Rectangle

4 90 degree angles

Rhombus

4 congruent sides

Circumference

The distance around a circle

Diameter

A chord that passes through the center of a circle