1.4: Measuring Segments and AnglesPrentice Hall Geometry
CEABD0-88-2-4-1246-6The numerical location of a point on a number line.Coordinate :On a number line length AB = AB =  |B - A|Length :On a number line, midpoint of AB = 1/2 (B+A) Midpoint :
Find which two of the segments XY, ZY, and ZW are congruent. Because XY = ZW,  XYZW.Measuring Segments and AnglesGEOMETRY  LESSON 1-4Find the length of each segment.XY = | –5 – (–1)| = | –4| = 4ZY = | 2 – (–1)| = |3| = 3ZW = | 2 – 6| = |–4| = 4
The Segment Addition PostulateIf three points A, B, and C are collinear and B is between A and C, then AB + BC = AC.ABC
AN = 2x – 6 = 2(8) – 6 = 10NB = x + 7 = (8) + 7 = 15Substitute 8 for x.If AB = 25, find the value of x. Then find AN and NB.Use the Segment Addition Postulate to write an equation.AN + NB = ABSegment Addition Postulate(2x – 6) + (x + 7) = 25	  Substitute.3x + 1 = 25	Simplify the left side.      3x = 24	Subtract 1 from each side.x = 8	Divide each side by 3.AN = 10 and NB = 15, which checks because the sum of the segment lengths equals 25.
RM = 5x + 9 = 5(15) + 9 = 84	MT = 8x – 36 = 8(15) – 36 = 84Substitute 15 for x.RM and MT are each 84, which is half of 168, the length of RT.Mis the midpoint of RT. Find RM, MT, and RT.Use the definition of midpoint to write an equation.RM = MTDefinition of midpoint5x + 9 = 8x – 36Substitute.5x + 45 = 8xAdd 36 to each side.      45 = 3xSubtract 5x from each side.        15 = xDivide each side by 3.RT = RM + MT= 168
Quiz1. T is in between of XZ. If XT = 12 and XZ = 21, then TZ = ?2. T is the midpoint of XZ. If XT = 2x +11 and XZ = 5x + 8, find the value of x.
Coordinate Plane
Parts of Coordinate Planey-axisQuadrant IIQuadrant I( - , + )( +, + )originx-axisQuadrant IIIQuadrant IV( - , - )( + , - )
DistanceOn a number line		formula: d = | x2 – x1 |On a coordinate plane		formula:
Find the distance between T(5, 2) and R( -4. -1) to the nearest tenth.
MidpointOn a number line		formula: On a coordinate plane	formula:
The midpoint of AB is M(3, 4). One endpoint is A(-3, -2). Find the coordinates of the other endpoint B.
Angles
Formed by two rays with the same endpoint.
The rays: sides
Common endpoint: the vertex
Name:
Measures exactly 90º

Measuring Segments and Coordinate Plane

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    1.4: Measuring Segmentsand AnglesPrentice Hall Geometry
  • 2.
    CEABD0-88-2-4-1246-6The numerical locationof a point on a number line.Coordinate :On a number line length AB = AB = |B - A|Length :On a number line, midpoint of AB = 1/2 (B+A) Midpoint :
  • 3.
    Find which twoof the segments XY, ZY, and ZW are congruent. Because XY = ZW, XYZW.Measuring Segments and AnglesGEOMETRY LESSON 1-4Find the length of each segment.XY = | –5 – (–1)| = | –4| = 4ZY = | 2 – (–1)| = |3| = 3ZW = | 2 – 6| = |–4| = 4
  • 4.
    The Segment AdditionPostulateIf three points A, B, and C are collinear and B is between A and C, then AB + BC = AC.ABC
  • 5.
    AN = 2x– 6 = 2(8) – 6 = 10NB = x + 7 = (8) + 7 = 15Substitute 8 for x.If AB = 25, find the value of x. Then find AN and NB.Use the Segment Addition Postulate to write an equation.AN + NB = ABSegment Addition Postulate(2x – 6) + (x + 7) = 25 Substitute.3x + 1 = 25 Simplify the left side. 3x = 24 Subtract 1 from each side.x = 8 Divide each side by 3.AN = 10 and NB = 15, which checks because the sum of the segment lengths equals 25.
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    RM = 5x+ 9 = 5(15) + 9 = 84 MT = 8x – 36 = 8(15) – 36 = 84Substitute 15 for x.RM and MT are each 84, which is half of 168, the length of RT.Mis the midpoint of RT. Find RM, MT, and RT.Use the definition of midpoint to write an equation.RM = MTDefinition of midpoint5x + 9 = 8x – 36Substitute.5x + 45 = 8xAdd 36 to each side. 45 = 3xSubtract 5x from each side. 15 = xDivide each side by 3.RT = RM + MT= 168
  • 7.
    Quiz1. T isin between of XZ. If XT = 12 and XZ = 21, then TZ = ?2. T is the midpoint of XZ. If XT = 2x +11 and XZ = 5x + 8, find the value of x.
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    Parts of CoordinatePlaney-axisQuadrant IIQuadrant I( - , + )( +, + )originx-axisQuadrant IIIQuadrant IV( - , - )( + , - )
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    DistanceOn a numberline formula: d = | x2 – x1 |On a coordinate plane formula:
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    Find the distancebetween T(5, 2) and R( -4. -1) to the nearest tenth.
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    MidpointOn a numberline formula: On a coordinate plane formula:
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    The midpoint ofAB is M(3, 4). One endpoint is A(-3, -2). Find the coordinates of the other endpoint B.
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    Formed by tworays with the same endpoint.
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