2-2
Conditional Statements
PART 1
Vocabulary
Review
Underline the conclusion of each statement.
1. If the weather is nice, we will go swimming.
2. If I exercise, then I will be strong.
3. If my friend works at her job this weekend, she won’t go to the movies on Saturday.
4. If I ride my bike to softball practice, then I will get there on time.
Vocabulary Builder
conditional (noun) kun DISH un ul
Other Word Form: condition (noun)
Definition: A conditional is an if-then statement.
Example: The statement, “If two angles are vertical angles, then they are congruent,”
is a conditional.
Use Your Vocabulary
Place a ✓ in the box of the statement is a conditional. Place an ✗ in the box if it
is not a conditional.
5. If an angle measures 90, then it is a right angle.
6. A pentagon is a polygon.
7. If points lie on the same line, they are collinear.
8. Work within parentheses, then multiply.
9. If x 5 6, then x 1 12 5 18.
10. A net is a two-dimensional diagram that you can fold to form a
three-dimensional figure.
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Related Words: hypothesis, conclusion
Key Concept Conditional Statements
Definition
Symbols
Diagram
A conditional is an if-then statement.
pSq
The hypothesis is the part p following if.
Read as “If p then q”
The conclusion is the part q following then.
or “p implies q.”
q
p
11. If p 5 tears and q 5 sadness, what are two ways to read p S q?
Problem 1 Identifying the Hypothesis and the Conclusion
Got It? What are the hypothesis and the conclusion of the conditional?
If an angle measures 130, then the angle is obtuse.
Complete each sentence with if or then.
12. The hypothesis is the part following 9.
13. The conclusion is the part following 9.
14. Circle the hypothesis. Underline the conclusion.
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If an angle measures 130, then the angle is obtuse.
Problem 2
Writing a Conditional
Got It? How can you write “Dolphins are mammals” as a conditional?
15. Circle the correct statement.
All dolphins are mammals.
All mammals are dolphins.
Underline the correct words to complete each statement.
16. The set of dolphins / mammals is inside the set of dolphins / mammals .
17. The smaller/larger set is the hypothesis and the smaller / larger set is the conclusion.
18. Use your answers to Exercises 16 and 17 to write the conditional.
If 9, then 9.
If an animal is
,
then it is
.
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Lesson 2-2, Part 1
Problem 3 Finding the Truth Value of a Conditional
Got It? Is the conditional true or false? If it is false, find a counterexample.
If a month has 28 days, then it is February.
19. Cross out the month(s) that have at least 28 days.
January
July
February
August
March
September
April
October
May
November
June
December
20. Is the conditional true or false? Explain.
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Lesson Check • Do you know HOW?
What are the hypothesis and the conclusion of the following statement? Write
it as a conditional.
Residents of Key West live in Florida.
21. Label the Venn diagram with the words Florida and Key West.
q
22. Circle the hypothesis. Underline the conclusion.
are residents of Key West
p
live in Florida
If people
,
then they
.
Lesson Check • Do you UNDERSTAND?
Error Analysis Your classmate rewrote the statement “You jog every Sunday” as "If
you jog, then it is Sunday." What is your classmate’s error? Correct it.
24. Circle the hypothesis and underline the conclusion of your classmate’s conditional.
If you jog, then it is Sunday.
25. Circle the counterexample for your classmate’s conditional.
You don’t jog, and it is not Sunday.
You also jog on Saturday.
26. Write the conditional that best represents “You jog every Sunday.”
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Chapter 2
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23. Now write the conditional.