It’s Go Time!
Answer the question:
 What is the next letter in the sequence?
D, H, L, P, . . .

A Q

B R
C
D
S
T
Draw a Counterexample

“If two rays have the
same endpoint, then they
are opposite rays.”
Answer the question!
 Identify the hypothesis of the conditional statement
“Two angles are complementary if the sum of their
measures is 90 degrees.”
 A if
 B Two angles are complementary
 C the sum of their measures is 90 degrees
 D Two angles are complementary if the sum of
their measures is 90 degrees.
Multiple Choice
Change the following statement into a conditional
statement:
“The sum of two odd numbers is even.”
A If two even numbers are added, then their
sum is even.
B
If an even and odd number are added, then their sum
is even.
C If two even numbers are multiplied, then their
product is odd
D If two odd numbers are added, then their
product is even.
Choose Wisely!




What is the inverse of the statement
“If two coplanar lines do not intersect, then they are
parallel”?
A If two coplanar lines do not intersect, then they are
not parallel.
B If two coplanar lines intersect, then they are not
parallel.
C If two lines are parallel, then they are coplanar and do
not intersect.
D If two coplanar lines are not parallel, then they
intersect.
Syllogism
Which conjecture is valid by the Law of Syllogism
for the following scenario?
“If Joe buys Nancy a card, he will give it to her. If Nancy
is having a birthday, then Joe will buy her a card.”
 A If Nancy is having a birthday, then Joe will give
her a card.
 B If Joe buys Nancy a card, then she
is having a birthday.
 C If Joe gives Nancy a card, then he bought the card.
 D If Joe gives Nancy a card, then she
is having a birthday.
Valid or Invalid
If you study for the test, then you will get an A.
You get an A.
Therefore, you studied for the test.
Valid or Invalid
If I am cool, then I love Geometry!
I am cool.
Therefore, I love Geometry.
What can you Conclude?
If Maria does not study, then she fails her test.
If Maria fails her test, then she will be
grounded. If Maria is grounded, then she
will not be able to go to the movies with her
friends. If Maria cannot go to the movies
with her friends, then Sally will steal Maria’s
friend.
Maria does not study.
Fill in the Blanks
 If two planes intersect, then their
intersection is a
 A line consists of at least
points.
 Two angles that form right angles are called
.
Which conjecture is true?
 A. An even number plus 3 is always even.
 B. An even number plus 3 is always prime.
 C. An even number plus 3 is always odd.
 D. A prime number plus 3 is always even.
Which law of logic allows the
conclusion?
For the past three weeks, the math team has been
meeting on Tuesday mornings. Sam concludes
that the math team will meet this Tuesday
morning.
A. Law of Detachment
B. Law of Syllogism
C. Inductive Reasoning
D. Deductive Reasoning
What is the converse?
“If there are clouds in the sky, then it is raining.”
A. If it is raining, then there are clouds in the sky.
B. If it is not raining, then there are clouds in the sky.
C. If it is raining, then there are no clouds in the sky.
D. If it is not raining, then there are no clouds in the sky.
How would you write the following
statement symbolically?
Let p represent “B is between A and C”
Let q represent “A, B, and C are collinear”
“If B is not between A and C,
then A, B, and C are not collinear.”
True or False?
If two odd numbers are multiplied,
then the product is an odd number.
What is the next item in the pattern?
-1, 2, -4, 8, …
A. -16
B. -4
C. 4
D. 16
Write as a conditional statement in
“if, then” form
“A number divisible by 10 is divisible by
5.”
Use the Transitive Prop to
complete the statement
If AB = CD and CD = EF, then …
Using Symbols
State the Law of Syllogism and
the Law of Detachment
Solve for x
2
x
+ 4x – 5 = 7
Solve the system of equations
3 x  2 y  7

 5 x  y  16