measuring segments
DESCRIPTION
Measuring Segments. Geometry Mrs. King Unit 1, Lesson 4. Ruler Postulate. 1-5: The points of a line can be put into a one-to-one correspondence with the real numbers so that the distance between any two points is the absolute value of the difference of the corresponding numbers. Practice. - PowerPoint PPT PresentationTRANSCRIPT
Measuring Segments
GeometryMrs. King
Unit 1, Lesson 4
Ruler Postulate
1-5: The points of a line can be put into a one-to-one correspondence with the real numbers so that the distance between any two points is the absolute value of the difference of the corresponding numbers.
Practice
Find QS (“the length of segment QS”) if the coordinate (“location”) of Q is –3 and the coordinate of S is 21.
213
24
24
Definition
Congruent: Two segments with the same length. ()
http://hotmath.com/hotmath_help/topics/congruent-segments/congruent-segments.gif
XY = | –5 – (–1)| = | –4| = 4
ZY = | 2 – (–1)| = |3| = 3
ZW = | 2 – 6| = |–4| = 4
Find which two of the segments XY, ZY, and ZW
are congruent.
Because XY = ZW, XY ZW.
Practice
Segment Addition Postulate
1-6: If three points A, B, and C are collinear and B is between A and C, then
AB + BC = AC.
A
B
C
AN + NB = AB(2x – 6) + (x + 7) = 25
3x + 1 = 25 3x = 24 x = 8
If AB = 25, find the value of x. Then find AN and NB.
AN = 2x – 6 = 2(8) – 6 = 10 NB = x + 7 = (8) + 7 = 15
Practice
PracticeIf DT = 60, find the value of x. Then find DS and ST.
D S T
2x - 8 3x - 12
Definition
Midpoint: a point that divides the segment into two congruent segments
Segment Bisector: a line, segment, ray, or plane that intersects a segment at its midpoint
RM = MT5x + 9 = 8x – 36
+36 +365x + 45 = 8x -5x -5x 45 = 3x 15 = x
M is the midpoint of RT. Find RM, MT, and RT.
RM = 5x + 9 = 5(15) + 9 = 84MT = 8x – 36 = 8(15) – 36 = 84
RT = RM + MT = 168
Practice
Homework
Measuring Segments in Student Practice Packet(Page 5, #1-12)