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Multimedia Geometry
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GEOMETRY
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CHAPTER1.5Y
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à 1.5èLïear Measurements
äèPlease answer ê followïg questions about lïear
measurements.
â
èèèèèèèèThe length ç a lïe segment is represented
èèèèèèèèuniquely by exactly one real number.
éS It is convenient at this time ë restate four defïitions that
will help us with lïear measurement.
Defïition 1.2.5èCOORDINATE:èIf poït A is located at a certaï real
number on a scaled numberlïe, ên that real number is ê coordïate
ç ê poït A.
Defïition 1.2.6èDISTANCE:èIf two poïts, A å B, are located on a
numberlïe, ên ê positive difference ç êir coordïates is ê
distance between A å B.
Defïition 1.2.9èLENGTH:èThe length ç a lïe segment determïed by
A å B is ê distance from A ë B.
Defïition 1.2.10èCONGRUENT:èTwo lïe segments are congruent if êy
have ê same length.
è Suppose we are given lïe segment ▒┤.èIf we thïk ç a ruler as part
ç a scaled numberlïe å place ▒┤ next ë ê ruler with one endpoït
at zero, ên ê oêr endpoït will be located at a coordïate that
equals ê length ç ▒┤.èThe length ç ▒┤ is designated by AB.èIn
oêr words, ê symbol AB without ê bar over ê ëp is used ë re-
present ê real number length ç ê lïe segment from A ë B.è
è You are encouraged at this poït ë go ë ê "measurement feature"è
ï this program å practice measurïg ê length ç lïe segments.èYou
will notice by defïitions 1.6 an 1.9 that if ê lïe segment is not
lïed up with one endpoït at zero, you can fïd ê length ç ê lïe
segment by subtractïg ê smaller endpoït coordïate from ê larger
endpoït coordïate.
è In measurïg lïe segments, we have assumed that ê length ç a seg-
ment is unique å that upon placïg ê segment with one endpoït at
zero êre is a unique poït on ê ruler a given distance from zero.
This ïnocent oversight is corrected by ê followïg axioms.
Axiom 6:èThe distance between two poïts A å B on ê numberlïe is
unique.
Axiom 7:èGiven a lïe segment with one endpoït at zero, êre is a
unique real number coordïate at ê oêr end.
è A third axiom allows us ë add two segment lengths ëgeêr ë get
ëtal length.
Axiom 8:èIf poït Q is between A å B, ên ê length ç ▒├ plus ê
length ç ├┤ equals ê length ç ▒┤.
Defïition 1.4.1èMIDPOINT:èThe midopït P ç segment ▒┤ is ê poït
halfway between A å B, such that AP = PB.è(Note that AP å PB re-
present ê lengths ç ▒└ å └┤.
Defïition 1.4.2èBISECTOR:èA bisecër ç a lïe segment is anoêrè
lïe, poït, or plane that passes through ê midpoït ç ê segment.
Axiom 9:èA lïe segment has a unique midpoït.
è You are encouraged at this poït ë go ë ê "construction feature"
ï this program å practice constructions (1) å (2).èConstruction (1)
ïvolves constructïg a congruent lïe segment, å construction (2)
ïvolves constructïg a bisecër ç a lïe segment.
1èèèèèèèFïd ê distance from C ë E.
èèèèèèèèèè
èèèèèèèèèèèAèèè Bèèèèè Cèèè E
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èèèèèèèè -3è-2è-1è 0è 1è 2è 3è 4è 5è 6
èèèèèèè
èèèèèèA)è8èèèè B)è2èèèè C)è3èèèè D)èNone
ü
è We can subtract ê smaller coordïate from ê larger coordïate.
èèèèèèèèèèèèèèèè5 - 3 = 2
Ç B
2èèèèèèèèFïd ê length ç ┤║.
èèèèèèèèèè
èèèèèèèèèèèAèèè Bèèèèè Cèèè E
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èèèèèèèè -3è-2è-1è 0è 1è 2è 3è 4è 5è 6
èèèèèèè
èèèèèèA)è4èèèè B)è3èèèè C)è5èèèè D)èNone
ü
è We can subtract ê smaller coordïate from ê larger coordïate.
èèèèèèèèèèèèèèèè5 - 0 = 5
Ç C
3èèèèèèèèèèèèFïd AC.
èèèèèèèèèè
èèèèèèèèèèèAèèè Bèèèèè Cèèè E
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èèèèèèèè -3è-2è-1è 0è 1è 2è 3è 4è 5è 6
èèèèèèè
èèèèèèA)è5èèèè B)è7èèèè C)è6èèèè D)èNone
ü
èèèèèèèèèèè AC means ê length ç ▒╖.
èèèèèèèèèèèèèè3 - (-2) = 3 + 2
èèèèèèèèèèèèèèèèèè = 5
Ç A
4èèèèèèèèèèèFïd AB + BC.
èèèèèèèèèè
èèèèèèèèèèèAèèè Bèèèèè Cèèè E
èèèèèèèè╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓¥
èèèèèèèè -3è-2è-1è 0è 1è 2è 3è 4è 5è 6
èèèèèèè
èèèèèèA)è5èèèè B)è7èèèè C)è6èèèè D)èNone
ü
èèèèèèèèèèè AC + BC = (0 - (-2)) + (3 - 0)
èèèèèèèèèèèèèèè = 2 + 3
èèèèèèèèèèèèèèè = 5
Ç A
5èèèèèèèèè Does AE equal EA?
èèèèèèèèèè
èèèèèèèèèèèAèèè Bèèèèè Cèèè E
èèèèèèèè╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓╓£╓╓¥
èèèèèèèè -3è-2è-1è 0è 1è 2è 3è 4è 5è 6
èèèèèèè
èèèèèèèèèèèèèA)èYesèèèè B)èNoèèè
ü
èèèèèèèèèèè AE = 5 - (-2) = 5 + 2 = 7
èèèèèèèèèèè EA = 5 - (-2) = 5 + 2 = 7èèèèèèèèèèèèèèè
Ç A
6èèè If AE = 5 å ▒║ ╧ ┤╜, ên BH is ______.
èèèèèèèèèè
èèèèèèèèèèèèèAèèBèèCèèEèèH
èèèèèèèèèèè ₧╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓¥
èèèèèèèèèèèèèèèèèèèèè
èèèè A)è5èèèè B)è15èèèèèC)è10èèèèèD)èNoneèèè
ü
èèèSïce ▒║ å ┤╜ are congruent, êy have ê same length, 5.èèèèèèèèèèèèèèèèèèèèèèèèè
Ç A
7èèèèIf CE = 12 å EH = 8, ên CH is _____.
èèèèèèèèèè
èèèèèèèèèèèèèAèèBèèCèèEèèH
èèèèèèèèèèè ₧╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓¥
èèèèèèèèèèèèèèèèèèèèè
èèèè A)è15èèèè B)è10èèèè C)è20èèèè D)èNoneèèè
ü
èèèèèèèèèèèèèèè CE + EH = CH
èèèèèèèèèèèèèèè 12 +è8 = 20èèèèèèèèèèèèè
Ç C
8è If AC is 10 å B is ê midpoït ç ▒╖, ên AB is _____.
èèèèèèèèèè
èèèèèèèèèèèèèAèèBèèCèèEèèH
èèèèèèèèèèè ₧╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓¥
èèèèèèèèèèèèèèèèèèèèè
èèèèè A)è5èèèè B)è7èèèè C)è4èèèè D)èNoneèèè
ü
èèèèèèèèèThe midpoït is ê halfway poït so
èèèèèèèèèèèèèèèèèAB = 5èèèèèèèèèèèèèèèèèèèèèè
Ç A
9èèèèèè If AH is 25, ên HA is _____.
èèèèèèèèèè
èèèèèèèèèèèèèAèèBèèCèèEèèH
èèèèèèèèèèè ₧╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓¥
èèèèèèèèèèèèèèèèèèèèè
èèèèè A)è50èèèè B)è25èèèè C)è12.5èèèèD)èNoneèèè
ü
èèèèèè The length ç AH is ê same as ê length ç HA.
èèèèèèèèèèèèèèèè HA = 25èèèèèèèèèèèèèèèèèèèèèè
Ç B
10èèèèè If ╖║ ╧ ║╜, ên E is ê _____ ç ╖╜.
èèèèèèèèèè
èèèèèèèèèèèèèAèèBèèCèèEèèH
èèèèèèèèèèè ₧╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓╓£╓╓╓¥
èèèèèèèèèèèèèèèèèèèèè
èè A)èCoplanarèè B)èComplementèèèC)èBisecërèè D)èNoneèèè
ü
èèIf ╖║ ╧ ║╜, ên ê lengths are ê same, so poït E bisects ╖╜.èèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèèè
Ç C