Name ___________________
Date _____________
Period ___________
Section 1-2: Measuring and Constructing Segments
Objectives: 1. Use length and midpoint of a segment.
2. Construct midpoints and congruent segments.
Ruler Postulate: __________________________________________________________________
_______________________________________________________________________________
How do you find the distance between two points?
To find the distance:
_______________________________________________________________________________
_______________________________________________________________________________
The distance between any two points is the ____________________ of the segment that connects
them.
The distance between E and J is EJ, the length of EJ .
EJ 
Length of a segment:
Use the figure above to find each length.
1. EG
2. EF
3. FH
Segment Addition Postulate: If B is between A and C, then AB + BC = ____
A
C
B
On PR , Q is between P and R. If PR  16,
we can find QR.
PQ  QR  PR
9  x  16
x7
QR  7
4.
5.
Find JK. ______
Find BC. ______
6.
7.
Find SV. ______
Find XY. ______
8.
9.
Find DF. ______
Find ST. ______
Congruent – objects that have the same __________ and __________.
Congruent Segments segments that have _______________________.
AB = BC
The length of AB equals the length of BC .
AB  BC
AB is congruent to BC .
Copying a Segment
Method
Sketch using estimation
Draw with a ruler
Constuct with a compass
and straightedge
Steps
Estimate the length of the segment. Sketch a segment that is about the
same length.
Use a ruler to measure the length of the segment. Use the ruler to
draw a segment having the same length.
Draw a line and mark a point on it. Open the compass to the lengthh of
the original segment. Mark off a segment on your line at the same
length.
Refer to triangle ABC above for Exercises 10 and 11.
10. Sketch LM that is congruent to AC .
11. Use a ruler to draw XY that is congruent to BC .
Construction – Congruent Segment
̅̅̅̅.
Construct a segment congruent to 𝐴𝐵
Draw l. Choose a point on l
and label it C.
Open the compass to the
distance of AB.
12. Use a compass to construct ST that is congruent to JK .
Place the point of the compass at
C and make an arc through l.
Find the point where the arc and l
intersect and label it D.
̅̅̅̅ ≅ 𝐴𝐵
̅̅̅̅
𝐶𝐷
Midpoint of a Segment: the point that _______________the segment __________________ segments.
In the figure, P is the midpoint of NQ .
13. PQ is congruent to _______________.
14. What is the value of x? _______________
15. Find NP, PQ, and NQ.
NP = _______
PQ = ________
NQ = ________
Bisect: _______________________________________
Segment Bisector: ______________, _______________, ______________, or ____________
____________________________________________________________________________.
Use the figure for Exercises 16–18.
16. Name the congruent segments in this figure.
17. Name the midpoint of BC .
18. Name the segment bisector of BC .
Use the figure for Exercises 19–21.
19. Name the congruent segments in this figure.
20. Name the midpoint of ZY .
21. Name the segment bisector of ZY .