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G e o m e t r y J o u r n a l 2 By Michelle Habie. Conditional Statement :. Conditional s tatement is formed by a hypothesis and a conclusion . It can be written in the form : If P then Q. Parts : If : hypothesis then : conclusion.
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Geometry Journal 2 By Michelle Habie
ConditionalStatement: Conditionalstatementisformed by a hypothesisand a conclusion. It can be written in theform: If P then Q. Parts: If: hypothesisthen: conclusion If I studygeometrythen I will pass the test. Iftheskyiscloudythenitwillraintoday. If I finish my homeworkthenI’mabletowatcht.v.
Counterexample: isanexamplethatprovesthat a conjectureisfalse. CounterExample: No mammals can fly. A bat is a mammal. Threepoints are allwayscollinear. Threepoints lay onthesameplanebutonlytwoofthem are collinear. All prime numbers are odd.2 is a prime number.
Definitionand Perpendicular Lines: Itis a conceptwritten in theformof a biconditionalstatementto describe a matematicalobject. Perpendicular lines are linesthatintersecteachotherforming a 90 degreeangle. A lineis perpendicular to a plane at a point. Thefloorof my housetothewalls. Theneedlesof a clockwhentheymatk 3 o’clock Thetrashholderisanexampleof a line perpendicular to a plane.
Bi- ConditionalStatement: A biconditionalstatementis a statementthat can be written in theformof P ifandonlyif Q. They are usedtowritemathemathicaldefinitions. They are importantto use in ourmathematicallanguageandeverydaylife. Anangleisright IFF itmeasures 90 degrees. A triangleisacute IFF the 3 angles are acute. 3x+1=25 IFF 3=8
DeductiveReasoning: Deductivereasoning uses logictofind a conclusionusingfacts. We use deductivereasoningtoapplythelawofdetachmentandthelawofsyllogism. Itisusedtorepresent a definitionusingsymbolsfor a betterunderstanding. Itworksmakingitsimplertounderstand. If I geton a dietthe I willlooseweight. IfI’m 18 yearsoldthen I willgetan ID. If I getan ID thenI’ll be ableto vote. Ifi’m 18 yearsoldthenI’ll be ableto vote. If I practicereadingthen my vocabularyskillswill be improven. SymbollicNotation: Itisusedtorepresent a definitionusingsymbolsfor a betterunderstanding. Itworksmakingitsimplertounderstand.
LawsofLogic: LawofDetachment: Ifpqistrueandpistrueitfollowsthatqisalsotrue. LawofSyllogism: Ifpqandqr are trueitfollowsthat prisalsotrue. Examples: If I am 16 yearsoldthen I can get my driverslicense. If I have a blackberrythen I amabletochatwithpeoplewhohavebb.If I chatwithpeoplewithbbthen I willkeep in touchwith my friends. Iftwoanglemeasure 45° thenthey are congruent. Iftwoangles are congruentthentheymeasurethesame.
AlgebraicProof: Analgebraicproofisanargumentthat uses logic, definitions, propertiesandprovenstatementstoprovethat a conclusionistrue. • 3x-2=7 Givenc. X=2 Given +2 +2 AdditionProp. ofEquality 4 MultiplicationPropofEquality 3x=9 DivisionProp. OfEqualityx=8 Simplify 3 3 Simplify x= 3 b. 3r= -12 Given 3 3 DiviionProp. OfEquality r=-4 Simplify
SegmentProp. ofEquality TheSegmentAdditionPostulatestatesthatthesumofthepiecesthatmake up a segmentisthesame as thelengthofthewholesegment. Thesamepropertyworksforandanglethatisdividedintotwoor more parts. Thesumofallthepartsisthesame as thewholeangle. Home Vista Herm. CAG Examples: a c e AC+ CE= AE Home-CAG= Home-VH+ VH-CAG G-P= G-P+P-E+E-P Guate Palin Escuintla Puerto
Two- columnProof: A two-columnproofiswrittenusingstatementsontheleftand a specificreasonforeachstatement in ordertofind a conclusiontoprovewhatisbeingaskedwith a process. Examples:
SegmentPropertiesofCongruence: Reflexive: Segment AB isonlyequalto AB. (itself). Symmetric: No matter how wename a segmentitisequaltoitself. (AB=BA) Transitive: If AB=BC and BC=CD then AB=CD. Examples: Home-CAG=CAG-Home Home CAG C=l L=P then, C= P isthatthey are thesame in lengthorheight.(TransitiveProp). Laura’s BB= My BB My BB= Monica’s BB Laura’s= Monica’s BB Carlos Luis Pablo Laura Me Monica
AnglePropertiesofCongruence: Reflexive: <BAC congruent <BAC. Symmetric: <BAC congruent <CAB. Transitive: If <XAW congruent <YAW , <YAW congruent <WAZ then <XAY congruent <WAZ. Examples: 1. 3. X <XYZ congruent <ZYX Y A D M A Z B E N 2. C O F B <ABC congruent <DEF ,<DEF congruent <MNO, and <ABC congruent <MNO. <ABC congruent <ABC C
Linear PairPostulate: Itis made up oftwoadjacentanglesthatshare a rayand are supplementary. Examples: 1. 2. C ABC and CBD are linear pairthenx+ 60= 180° X= 120° X 60 A B D X+10+ 100= 180° X+110=180° X=180-110 X=70° B 3. A 100 X+10 ACB+ BCD= 180 ACB and BCD are linear pair. C D
CongruentSupplementsTheorem: Iftwoangles are supplementsofthesameanglethenthetwoangles are congruent. Examples: 1. 2. <CBD is a supplementto <ABC and <YXZ isalso a supplementto <ABC SO, <CBD and <YXZ are congruent. Y C B A D X Z <1 issuppto <3 <2 issuppto <3 So, <1 iscongruentto <2. 110° 70° 70° <1 <2 <3
<a <b 3. < c If <a issuppto <c Then <bisalsosuppto <c.
Vertical Angles: Vertical angles are formedwhentwolines cross andtheoppositeangles are vertical andcongruent. In vertical anglesoppositeones (acrosseachother) measurethesame. Examples: If <a and <c are vertical then X-5 + 100 X= 100+5 X=105 X-5 2 <1 and <3 are vertical. a 3 1 a a 4 a 100
X+16 X+16= 2x-6 16+6= 2x-x 22+x 2x-6
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