DefinitionsTrue / False Postulates and Theorems Lines and Angles Proof

Definitions Answer: Conjecture An unproven statement based on observation is called a...

Definitions Answer: Perpendicular Lines Lines that intersect to form right angles are called...

Definitions A conditional statement that is formed by switching the hypothesis and the conclusion is called a… Answer: Converse

Definitions A ray that divides an angle into two adjacent angles that are congruent is called an… Answer: Angle Bisector

Definitions A true statement that follows as the result of other true statements is... Answer: a Theorem

True / False Answer: True. They are: There are only three lines parallel to

True / False Answer: True. There are four pairs of corresponding angles formed by a transversal. Pair #1: angles 1 and 3 Pair #2: angles 2 and 4 Pair #3: angles 5 and 7 Pair #4: angles 6 and 8

True / False Answer: False! Because we have congruence symbols, and not equal signs, it should say the “transitive property of congruence” not “equality” The transitive property of equality states that: If and then

True / False Answer: True If the transversal below cuts two parallel lines, and angle 5 measures 30 degrees, then angle 4 measures 30 degrees. Alternate Exterior Angles Theorem

True / False Answer: False. They are supplementary. The Consecutive Interior Angles Theorem: If two parallel lines are cut by a transversal, then the consecutive interior angles formed are complementary.

Postulates and Theorems Answer: Segment Addition Postulate Name the postulate below:

Postulates and Theorems Answer: Angle Addition Postulate Name the postulate used in this problem.

Postulates and Theorems Answer: Alternate Interior Angles Theorem Name the theorem.

Postulates and Theorems Answer: Postulates are claims or statement that are assumed without proof; something taken as self-evident Theorems are true statements that follow as the result of other true statements. How are postulates different from Theorems?

Postulates and Theorems Answer: Congruent Supplements Theorem What is the name of this theorem? If two angles are supplementary to the same angle then they are congruent.

Lines and Angles Answer: Transversal What kind of line is t?

Lines and Angles Answer: Skew (Not coplanar, and in different directions) What kinds of lines are these?

Lines and Angles Answer: by the linear pair postulate Find x and y. State your reasons. by the Alternate Exterior Angles Theorem

Lines and Angles Answer: by the corresponding angles postulate, we know that Find the value of x.

Lines and Angles Answer: Angles 1, 5, 4, and 8 are 107 Angles 2, 6, 3, and 7 are 73

Proof Answer: Triangle Sum Conjecture Name the conjecture:

Proof Answer: Two-column proof Paragraph proof Flow proof Name the three types of proofs we’ve discussed in class.

Proof Answer: Consecutive Interior Angles Theorem Name the missing theorem.

Proof Answer: Symmetric Property of Equality: if 7 = x, then x = 7 Reflexive Property of Equality: for any x, x = x for any segment AB, AB = AB Transitivity is one of three properties of equality that we use in proofs. What are the other two?

Proof Answer: Definitions, Theorems, Properties, and Postulates In a two-column proof, what can kinds of “things” be written under the reasons column? (Hint: there are four)