Download Holt McDougal Geometry 1-2

1-2
Measuringand
andConstructing
ConstructingSegments
Segments
1-2 Measuring
Warm Up
Lesson Presentation
Lesson Quiz
Holt McDougal
Geometry Geometry
1-2 Measuring and Constructing Segments
Warm Up
Simplify.
1. 7 – (–3) 10
2. –1 – (–13) 12
3. |–7 – 1| 8
Solve each equation.
4. 2x + 3 = 9x – 11
2
5. 3x = 4x – 5
5
6. How many numbers are there between
Infinitely many
Holt McDougal Geometry
and
?
1-2 Measuring and Constructing Segments
Objectives
Use length and midpoint of a segment.
Construct midpoints and congruent
segments.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
one
A) A point corresponds to __________
number on a number line/ruler.
coordinate
The number is called a _____________.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
B) The distance between any two points is
the ________________of
the difference of
absolute value
the coordinates.
The distance is also called the ________.
length
A
-5
Holt McDougal Geometry
B
4
AB = |-5 – 4| = |-9| = 9
1-2 Measuring and Constructing Segments
C) Congruent
_________________
segments are segments that
have the same length.
__________are
Tick marks
used in a figure to show
congruent segments.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
In order for you to say that a point B is between
two points A and C, all three points must lie on the
same line, and AB + BC = AC.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
Example 1
B is between A and C, AC=14, and BC=11.
Find AB.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
Example 2
Ex 2: S is between R and T.
RS=2x+7, RT=28, and ST=4x.
Find x and ST.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
midpoint
D) The _________
, M, of AB is the point
bisects
that ________,
or divides, the segment
into two congruent segments.
A
Holt McDougal Geometry
M
B
1-2 Measuring and Constructing Segments
• A segment bisector is any ray, segment, or line
that intersects in a segment as its midpoint.
It divides the segment into two equal parts at its
midpoint.
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
Example 3
B is the midpoint of AC. AB=5x, and BC=3x+4.
Find x and AC.
5x = 3x + 4
2x = 4
x=2
AC = 5(2) + 3(2) + 4
AC = 20
Holt McDougal Geometry
1-2 Measuring and Constructing Segments
Example 4
S is the midpoint of RT. RS=-2x and RT=-6x-4.
Find x, RS, and RT.
-6x - 4 = 2(-2x)
-6x - 4 = -4x
-2x = 4
x = -2
RS= -2(-2)
RS= 4
Holt McDougal Geometry
RT= -6(-2)-4
RT= 8