Geometry Definitions, Chapter 2

Front 1

conditional statement

Back 1

consists of two clauses, ohypothesis & conclusion
a → b or "If a, then b."

Front 2

Euler diagrams

Back 2

used to see how conditional statements relate to each other

Front 3

converse

Back 3

converse of conditional statement found by interchanging its hypothesis and conclusion.
The converse of a → b is b → a

Front 4

converse of true statement

Back 4

may be false

Front 5

For definitions

Back 5

converse always true;
a if and only if b
a iff b
a ↔ b

Front 6

syllogism

Back 6

Argument of the form
a → b
b → c
Therefore, a → c

Front 7

Theorem

Back 7

statement that is proved by reasoning deductively from already accepted statements

Front 8

Direct proof

Back 8

premises lead to conclusion, or theorem

Front 9

Indirect proof

Back 9

start with assumption that is opposite of desired conclusion, reach contradiction; contradiction will indicate that assumption false and desired conclusion must be true

Front 10

postulate

Back 10

statement that is assumed to be true without proof

Front 11

Postulate 1

Back 11

Two points determine a line

Front 12

Postulate 2

Back 12

Three noncollinear points determine a plane

Front 13

Pythagorean Theorem

Back 13

The square of the hypotenuse of a right triangle is equal to the sum of the squares of the other two sides

Front 14

Triangle Angle Sum Theorem

Back 14

The sum of the angles of a triangle is 180º

Front 15

Two Circles Theorems

Back 15

If the diameter of a circle is d, its circumference is πd.
If the radius of a circle is r, its area is πr².