Proofs Flashcards
Given: Vertical Angles
Vertical Angles are Congruent
What should be done when given that segments bisect?
GIVEN: __ & __ bisects each other OR ___ bisects ____
1. Statement: ______ is the midpoint
1. Reason: A segment bisector meets at the midpoint
2. Statement: ______ congruent ________
2. A midpoint divides a segment into two congruent segments
How can supplementary angles be used in a proof? (4)
Two angles must have been proven congruent (X & Y)
- Statement: X & A are supplementary and Y & Z are supplementary
- Reason: Linear Pairs are Supplementary
- Statement: A = Z
- Supplements of congruent angles are congruent
What should be done when given that angles bisect?
GIVEN: ___ bisects ____
Statement: ______ = _____
Reason: An angle bisector divides an angle into two congruent angles
What must be done before proving two sides are congruent through addition and substractiction?
AC - BC = EC - DC
AB = ED
AC must be proven congruent to EC
BC must be proven congruent to DC
How do you prove right angles?
Perpendicular Lines form right angles
How do you prove that the parts of two congruent sides are congruent?
Given: AB = CD, E mp of AB and F mp of CD
(Note: DO NOT NEED TO PROVE THAT THE PARTS OF THE SAME SIDEARE CONGRUENT)
- Statement: EB = 0.5 AB & FD = 0.5 CD
- Reason: Midpoint divides a segment in one half
- Statement: 0.5 AB = 0.5 CD
- Reason: Multiplication
- Statement: EB = FD
- Reason: Substitution
How can an Isosceles Triangles be used in Proofs? (2)
- In a triangle, angles opposite congruent sides are congruent
- In a triangle, sides opposite congruent angles are congruent
How do you prove parallel lines? (2)
- If 2 lines are cut by trans. such that (alt. int./corr./alt. ext.) angles are congruent, lines are parallel
- If 2 lines are cut by trans. such that cons. int. angles are supp., lines are parallel
How do you use parallel lines in a proof? (2)
- If 2 parallel lines are cut by trans, then (alt. int./corr./alt. ext.) angles are congruent
- If 2 parallel lines are cut by trans, cons. int. angles are supplementary
How to prove two triangles are congruent?
- SAS
- ASA
- AAS
- HL
How to prove two triangles are similar in proofs?
AA similarity Theorem
2 angles in one triangle are congruent to 2 angles in another triangle
How do you utilize parts of congruent & similar triangles?
- Corresponding Parts of Congruent Triangles are Congruent
- Corresponding Parts of Similar Triangles are Similar
How do you prove that two sides of similar triangles are in proportion and the products of the sides are in proportion?
- Prove Triangles are Similar through AA Sim. Theorem
- Corresponding Sides o Similar Triangles are in Proportion
- Products of Means = Products of Extremes
What are three ways to prove an isosceles trapezoid?
- Must have at least one pair of congruent opposite sides
- Each pair of base angles are congruent
- Diagonals are congruent