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Geometry Final Sem. 1
Vocabulary words and formulas. Chapters 1-4.
69
Mathematics
9th Grade
12/17/2009

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Cards

Term

Give the definition of:

geometry

Definition

geometry is the study of six broad categories:

1. points

2. lines

3. angles

4. curves

5. surfaces

6. solids

Term

Reasoning in geometry consists of three stages; name all three.

Hints: 1. music-art, 2. observation, 3. test

Definition

1. Look for a pattern.

2. Make a conjecture

3. Verify the conjecture

Term
Define conjecture.
Definition
an unproven statement based on observations
Term
Define inductive reasoning.
Definition
a process of looking for patterns and making conjectures
Term
To prove a conjecture as false, you must provide a _____________.a
Definition
counterexample
Term
Define counterexample.
Definition
something that proves a conjecture to be false
Term
To find the sum of first positive odd integers, you must...
Definition

square the number of integers.

Example:

first two odd integers: 1+3=4, or 22

first three odd integers: 1+3+5= 9, or 32

Term
Uh... define defintion.
Definition
use known words to define an unknown word
Term
Define point.
Definition
represented by a small dot, cannot be measured
Term
Define line.
Definition
straight, extends forever in two directions
Term
Define plane.
Definition
flat surface, has no thickness- 2D only- extends forever in 4 directions
Term
Define collinear.
Definition
two or more points on the same line
Term
Define coplanar.
Definition
two or more points in the same plane (three points will always be on the same plane)
Term
Rules accepted without proof are called _________ or _______.
Definition

postulates

axioms

Term
Rules that are proved are called _________.
Definition
theorems
Term
Distance formula.
Definition
AB=√(x2-x1)2+(y2-y1)2
Term
When do you use the distance formula?
Definition
When you have the coordinates of points on a graph.
Term
The symbol for congruence is...
Definition
= with a ˜ on top
Term
What is the Pythagorean Theorem?
Definition
a2+b2=c2
Term
Angles that have the same measure are called _________ angles.
Definition
congruent
Term
Types of angles:
Definition

acute

right

obtuse

straight

Term
Define bisect.
Definition
to split/divide something into two sections/equal parts.
Term
Define segment bisector.
Definition
segment, ray, line, or plane that intersects the segment at its midpoint
Term
What is the midpoint formula?
Definition

m (x,y)= (x2+x1, y2+y1)

 


               (2, 2)

 

Term
Two angles are _______ angles if their sides form two pairs of opposite rays.
Definition
vertical
Term
Two adjacent angles are a linear pair if their ____________ sides are opposite rays.
Definition
noncommon
Term
The sum of the measures of angles that form a linear pair is ___°
Definition
180
Term
Two angles are __________ angles if the sum of their measures is 90°
Definition
complementary
Term
Two angles are ____________ angles if the sum of their measures is 180°
Definition
supplementary
Term
Define conjecture.
Definition
an unproven statement based on observations.
Term
Define inductive reasoning.
Definition
a process of looking for patterns and making conjectures.
Term
Define counterexample.
Definition
something that proves a conjecture to be false.
Term
Define definition.
Definition
use known words to define an unknown word.
Term
Define postulate.
Definition
a basic belief, principle; an axiom
Term
Define vertical angles.
Definition
two nonadjacent angles formed by two intersecting lines (think of an )
Term
Define linear pair.
Definition
adjacent angles whose non-common sides are opposite rays.
Term
Define conditional statement.
Definition
if-then form of a two-part statement.
Term
What do you do to write the converse?
Definition
Flip hypothesis and conclusion.
Term
What do you do to write the inverse?
Definition
Negate both.
Term
What do you do to write the contrapositive?
Definition
Flip and negate hypothesis and conclusion.
Term
Define biconditional statement.
Definition

-part converse and conditional

-only-if form

-order of conditional

Term
Define theorem.
Definition
a true statement that follows from other true statements.
Term
A two-column proof is has...
Definition

1. numbered statements and reasons

 

2. shows the logical order of an argument

Term
Define paragraph proof.
Definition
same information as a two-column proof, but is written in sentences.
Term
Define transversal.
Definition
a line that intersects two or more coplanar lines in different points.
Term
Describe the distinct characteristics of an equilateral triangle.
Definition
3 congruent sides
Term
Describe the distinct characteristics of an isosceles triangle.
Definition
2 congruent legs
Term
Describe the distinct characteristics of a scalene triangle.
Definition
No congruent sides.
Term
An acute triangle has _ acute angles.
Definition
3
Term
An equiangular triangle has _ congruent angles.
Definition
3
Term
A right triangle has _ right angle.
Definition
1
Term
An obtuse triangle has _ obtuse angle.
Definition
1
Term
interior angles
Definition
inside angles
Term
exterior angles
Definition
angles adjacent to interior angles
Term

Theorem 4.1: Triangle Sum Theorem

The sum of the measure of the _______ angles of a ________ is ___.(degrees)

Definition

interior

triangle

180

Term

Theorem 4.2: Exterior Angle Theorem

The measure of an exterior angle of a triangle is equal to the ___ of the measures of the two _____________ interior angles

Definition

sum

nonadjacent

Term
What is a corollary to a theorem?
Definition
a statement that can be proved easily using the theorem
Term

Corollary to the Triangle Sum Theorem:

The _____ angles of a _____ triangle are ____________.

Definition

acute

right

complementary

Term
congruent figures
Definition
figures exactly the same size and shape
Term

Theorem 4.3: Third Angles Theorem

If two _______ of one triangle are congruent to two ______ of another triangle, then the third angles are also _______.

Definition

angles

angles

congruent

Term
Postulate 19: SSS Congruence Postulate
Definition
If three sides of one triangle are congruent to three sides of a second triangle, then the two triangles are congruent.
Term
Postulate 20: SAS Congruence Postulate
Definition

Side-Angle-Side

If two sides and the included angle of one triangle are congruent to two sides and the included angle of a second triangle, then the two triangles are congruent.

Term
Theorem 4.6: Base Angles Theorem
Definition
If there is an isosceles triangle, the two base angles will be congruent.
Term
Theorem 4.7: Converse of the Base Angles Theorem
Definition
If two base angles are congruent, then it is an isosceles triangle.
Term
Corollary to Theorem 4.6
Definition
If a triangle is equilateral, then it is equiangular.
Term
Corollary to Theorem 4.7
Definition
If a triangle is equiangular, then it is equilateral.
Term
Postulate 21: ASA Congruence Postulate
Definition
If two angles and the included side of one triangle are congruent to two angles and the included side of another triangle, then the triangles are congruent.
Term
Theorem 4.5: AAS Congruence Theorem
Definition
If two angles and the excluded side of one triangle are congruent to two angles and the excluded side of another triangle, then the triangles are congruent.
Term
coordinate proof
Definition
involves placing geometric figures in a coordinate plane
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