# Mid year exam vocab

## 90 terms

### symmetry

is a geometry characteristic of both nature and art

### reflectional symmetry

is a design where you can fold along aline of symmetry so that all the points on one side of the line exactly concide with all the other points on the other side of the line

### bilateral symmetry

is an object with reflectional symmetry looks balanced and has only one line of symmetry

### ratational symmetry

a design where it looks the same after it around a point by less than a full circle

### compass

is a geometrical tool used to construct circles and mark off equal distance

### straight edge

is a geometrical tool is like ruler but has no marks

### regular hexagon

is a six sided figure whose sides are the same are the same length and whose angles are all the same size

### line

is a straight, continous arrangement of infinitely many points; infinite length but no thickness, extends forever in two directions

### plane

has length and width but with no thickness

### definition

is a statement that clarifies or explains the meaning of a word or a phase

### collinear

means on the same line

### coplanar

means on the same plane

### line segment

consists of two points (endpoints) of the segment and all the points between that are collinear with the two points

### congruent segment

are two segments that have the same measure or length and only iff

### midpoint

is the point if a segment that is the same distance from both endpoints

### bisect

to divide into two congruent segments

### ray

begins at a point and extends infinitely in one direction

### angle

is formed by two rays that share a common endpoint, provided that the two are non collinear

### vertex

is the common endpoint of the two rays

the two rays

### measures of an angle

is the smallest amount of rotation about the vertex from one ray to the other, measured in degrees

### degrees

the measure of an angle can be any value between 0 degrees and 180 degrees

### protactor

is the geometry tool you use to measure an angle

### congruent angles

are two angles that have the same measure and only iff

### angle bisector

is a ray that contains the vertex and divides the angle into two congruent angles and only iff

### counterexample

is a figure that fits your definition but isn't what you're trying to define

### right angle

is a 90 degree angle

### acute angle

is an angle smaller than 90 degrees

### obtuse angle

is an angle that is larger than 90 degrees

### polygon

is a closed figure in a plane formed by connecting the line segments endpoint to endpoint with each segment intersecting exactly two others

### side of a polygon

each line segment

### vertex of the polygon

each endpoint where the sides meet

### diagonal of a polygon

is a line segment that connects two nonconsecutive vertices

### convex

is a polygon with no diagonal on the outside of the polygon

### concave

is a polygon with at least one diagonal on the outside of the polygon

### congruent polygons

are two polygons where they are exactly the same size and shape iff only iff

### equilateral polygon

all sides have equal length

### equiangular polygon

all the angle have equal measure

### regular polygon

is both equilateral and equiangular

### assume

is to accept it as true without proof or facts

### scalene triangle

is a triangle where none of the sides have equal measure

### equilateral triangle

is a triangle where all sides are equal in measure

### isosceles triangle

is a triangle where two sides have the same measure

### vertex angle

is the angle between the two sides of equal length in an isosceles triangle

### base

the opposite side of the vertex angle

### base angles

are the two angles opposite the two sides of equal length in an isosceles triangle

### parallelogram

is a quadrilateral with two sets of parallel lines

### rhombus

is an equilateral quadrilateral with 2 sets of parallel lines

### circle

is the set if all point a plane at a given distance (radius) from a given point (center) in the plane

a segment from the center to a point on the edge of the circle

### diameter

is a line segment containing the center with its endpoints on the circle

### congruent circles

when two or more circles have the same radius and only iff

### concentric circles

when two or more coplanar circles share the same center

### arc of an circle

when two points on the continuous part of the circle between two points

### semicircle

is an arc of a circle whose endpoints are the endpoints of a diameter

### minor arc

is an arc of a circle that is smaller than a semicircle

### major arc

is an arc of a circle that is larger than a semicircle

### arc measure

measuring the central angle and side passing through the endpoints of the arc

### central angle

the angle within its vertex at the center of the circle

### chord

a diagonal inside the circle from edge to the other

### tangent

a line that shares a point with the circle on the outside of the circle

### locus

the set of points

### inductive reasoning

is the process of observing data, recognizing patterns, and making generalizations about those patterns

### conjecture

a generalization based on inductive reasoning

### deductive reasoning

is the process of showing that certain statements follows logically from agreed upon assumptions and proven facts

### function rule

the rule that gives the nth term for a sequence

### paragraph proof

a logical explanation, written as a paragraph

### converse

switches "if" and "then" of a conjecture

### transversal

a line intersecting two or more other lines in the plane

### slope triangle

a way to find slope

### sketch

doesn't require geometry tools

### draw

requires a protractor and a ruler

### construct

requires a compass and a straightedge

### segment bisector

is a line, ray or segment in a plane that passes through the midpoint in a plane

### perpendicular bisector

a segment has many perpendiculars and many bisectors, but each segment in a plane has only one bisector that is also perpendicular to the segment

### median

the segment connecting the vertex of a triangle to the midpoint of its opposite side

### mid segment

the segment that connects the midpoints of two sides of a triangle

### distance from a point to a line

is the length of perpendicular segment from a vertex to the opposite if ti a line containing the opposite side

### angle bisector

divides an angle into 2 congruent angles

### parallel lines

are lines that lie the same place and do not intersect

### concurrent

when three or more lines have a common point

### point of concurrency

the point of concurrency for the three angle bisectors

### incenter

the point of concurrency for the three angle bisectors

### orthocenter

the point of concurrency for the three altitudes

### circumcenter

the point of concurrency for the perpendicular bisectors

### circumscribed

is a circle that touches each side of the polygon at exactly one point

### legs

the other two sides that aren't the base

### included angle

an angle that is included between two sides of a triangle

### included side

a side that is included between the two angles of a triangles