Download 2.3 - Biconditionals and Definitions.notebook

2.3 ­ Biconditionals and Definitions.notebook
October 02, 2015
10/2: Warm Up
1. Underline the hypothesis and circle the conclusion:
"If a figure is a triangle, then it has 3 sides"
2. Write the converse, inverse, and contrapositive of the following.
"If a figure is a square, then it is a rectangle"
Converse ­
Inverse ­
Contrapositive ­
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2.3 ­ Biconditionals and Definitions.notebook
2.3: Biconditionals & Definitions
October 02, 2015
Date:10/2
A biconditional is a single true statement that combines a true
conditional and its true converse. You can write a biconditional by
joining the two parts of each conditional with the phrase
______________________________.
Ex 1). What is the converse of the following true conditional? If the
converse is also true, combine the statements as a biconditional.
Conditional: If the sum of the measures of two angles is 90, then the
angles are complementary.
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2.3 ­ Biconditionals and Definitions.notebook
A biconditional combines
October 02, 2015
and
as _______________
ex: A point is a midpoint if and only if it divides
a segment into two congruent segments.
Ex 2). What are the two conditional statements that form this
biconditional?
Two numbers are additive inverses if and only if their sum is 0.
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2.3 ­ Biconditionals and Definitions.notebook
October 02, 2015
What makes a good definition?
1. A good definition uses clearly understood terms.
2. A good definition is precise.
3. A good definition is reversible. It can be written as a true biconditional.
Ex 3). Is this definition of an equilateral triangle reversible? If yes, write it
as a true biconditional.
An equilateral triangle is a triangle with 3 congruent sides.
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2.3 ­ Biconditionals and Definitions.notebook
October 02, 2015
Ex 4). Which of the following is a good definition?
[A]
Dogs are animals with 4 paws.
[B]
Squares have 4 sides.
[C]
Tuesday is the day before Wednesday.
[D]
An acute angle has a small measure.
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2.3 ­ Biconditionals and Definitions.notebook
October 02, 2015
Homework:
pg. 108 #1 – 3, 8 – 26(e), 45 – 50
Advertisement Project Presentations ­ Tuesday 10/13
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2.3 ­ Biconditionals and Definitions.notebook
October 02, 2015
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