Advanced Geometry Section 2.5 and 2.6

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Presentation transcript:

Advanced Geometry Section 2.5 and 2.6 Addition, Subtraction, Multiplication, and Division Properties

Addition, Subtraction, Multiplication and Division Properties I CAN… Use the addition, subtraction, multiplication and division properties Write proofs involving the addition, subtraction, multiplication and division properties

Quick Review Define complementary angles Define supplementary angles Define congruent segments Define congruent angles Two angles are complementary if their sum is 90° Two angles are supplementary if their sum is 180° Two segments are congruent if their measures are equal. Two angles are congruent if they have the same measure.

Theorems If a segment is added to two congruent segments, the sums are congruent. (Addition Property)

Theorems If an angle is added to two congruent angles, the sums are congruent (Addition Property) Note that we first need to know that we have 2 congruent angles, then that we are adding the same angle to both

Theorems If congruent segments are added to congruent segments, the sums are congruent. (Addition Property)

Theorems If congruent angles are added to congruent angles, the sums are congruent. (Addition Property)

Theorems If a segment (or angle) is subtracted from congruent segments (or angles), the differences are congruent. (Subtraction Property)

Theorems If a segment (or angle) is subtracted from congruent segments (or angles), the differences are congruent. (Subtraction Property)

Using the Addition and Subtraction Properties An addition property is used when the segments or angles in the conclusion are greater than those in the given information A subtraction property is used when the segments or angles in the conclusion are smaller than those in the given information.

Statements Reasons 1. Given 2. How to use this theorem in a proof: Conclusion: Statements Reasons 1. Given 2. 2. Subtraction

Multiplication Property If segments (or angles) are congruent, then their like multiples are congruent. If B, C, F, and G are trisection points and then by the Multiplication Property. A B C D E F G H

Division Property If segments (or angles) are congruent, then their like divisions are congruent. If are angle bisectors, then by the division property. D Z O G C S A T

Using the Multiplication and Division Properties in Proofs Look for a double use of the word midpoint, trisects, or bisects in the “Given.” Use multiplication if what is Given < the Conclusion Use division if what is Given > the Conclusion

Example Given: Prove: Statements Reasons R is the midpoint of O is the midpoint of R is the midpoint of Prove: Statements Reasons M O P N R S

More Examples and Homework Read Sample Problems 2 through 4 on pages 90 and 91. HW: p. 86 #4-6, 11; p. 91 #1, 3, 4, 11, 12 Don’t forget to draw all the diagrams!!!!!