Download Section 2.2 Day 2 Definitions and Biconditional Statements

Week 6
Warm Up
1) write an equation that passes through the
given point and y-intercept.
( 2, 1 ) ; b = 5
09.23.11
Geometry
2.2 Day 2
Rule 1
Rule 2
I will recognize and use definitions
to rewrite statements.
Statements must be first written in “if – then” form
or biconditional form.
If the statement or its converse is false you
must give a counter example.
Ex 1
Statement:
x = 3 if and only if x2 = 9.
Proper form?
Yes – biconditional.
Conditional Statement:
If x = 3, then x2 = 9.
Converse Statement:
If x2 = 9 then, x = 3.
Answer:
True False
Counter Example:
Conditional statement is true,
but the converse is false
because x can equal -3.
Rule 3
Ex 2
If the statement and its converse are true
write it in biconditional form.
Statement:
Adjacent Angles share a common side.
Proper form:? No
If – then:
If two angles are adjacent,
then they share a common side
Converse:
If two angles share a common side,
then they are adjacent.
Answer:
True False
Biconditional:
Two angles are adjacent if and only if
they share a common side.
Algebra
Ex 3
Statement:
If 3x + 2 = x + 12, then x = 5.
Proper form:?
Yes
Converse:
If x = 5, then 3x + 2 = x + 12
Answer:
True False
Biconditional:
3x + 2 = x + 12 if and only if x = 5
Review
Do: 1
If the statement or its converse is false you
must give a ______ ______.
Write as a biconditional statement:
A rectangle is a square
when it has four congruent sides.
Assignment:
Textbook Page 83, 29 – 43 ODDS.