# 10th Grade Geometry - Chapter 2

## 18 terms

### law of syllogism

if p ➡q and q➡r are true conditional statements then p➡r is true

### biconditional statement

a statement that contains the phrase "if and only if" the symbol for "if and only if" is ↔

### theorem

a true statement that follows as a result of other true statements

### equivalent statement

two statements that are both true of both false

### line perpendicular to a plane

a line that intersects the plane in in a point and is perpendicular to every line in the plane that intersects it

### converse

the statement formed by switching the hypothesis and conclusion of a conditional statement

### hypothesis

the "if" part of a conditional statement

### conditional statement

has two parts, a hypothesis and a conclusion.

### two-column proof

a type of proof written as numbered statements and reasons that show the logical order of an argument

### conclusion

the "then" part of a conditional statement

### perpendicular lines

two lines that intersect to form a right angle. the smybol for "is perpendicular to" is ⊥

### negation

the negative of a statement. the negation symbol is ~

### law of detachment

if p ➡ q is a true conditional statement and p is true, than q is true

### paragraph proof

a type of proof written in paragraph form

### if-then form

the "if" part contains the hypothesis and the "then" part contains the conclusion.

### logical argument

an argument based on deductive reasoning, which uses facts, definitions, and accepted properties in a logical order

### contrapositive

the statement formed when you negate the hypothesis and conclusion of the converse of a conditional statement

### inverse

the statement formed when you negate the hypothesis and conclusion of a conditional statement