Construction in geometry: congruent segments and angles, perpendicular bisectors and angle bisectors.

1. BASIC CONSTRUCTIONS
Congruent Segments, Congruent Angles, Perpendicular
Bisectors, Angle Bisectors

2. WHAT CONSTRUCTION MEANS IN GEOMETRY?
 To construct geometric figures in geometry
we use only two tools: a straightedge and a
compass.
 In this lesson you will learn some basic
constructions.
 Congruent segments (we did this in class)
 Congruent angles (we did this in class)
 Perpendicular bisectors
 Angle bisectors

3. REVIEW OF CONGRUENT SEGMENTS AND
ANGLES
 How to construct congruent segments.
 https://www.youtube.com/watch?v=oszaihGRIZ4
 How to construct congruent angles.
 https://www.youtube.com/watch?v=sfO1sAWO0sM

4. DEFINITIONS
 Perpendicular lines: Lines that intersect to
form right angles.
 Perpendicular bisector: A line, segment, or
ray that is perpendicular to the segment at its
midpoint.

5. CONSTRUCT A PERPENDICULAR BISECTOR
 https://www.youtube.com/watch?v=WkA_AstSu7Y&list=PLC
026D398EB6FAC31

6. CONSTRUCT ANGLE BISECTOR
 https://www.youtube.com/watch?v=qBw0Ly-
wF4U&index=6&list=PLC026D398EB6FAC31

7. ERROR ANALYSIS
 Bring your answer to class!
Your friend constructs 𝑋𝑌 so that it is
perpendicular to and contains the midpoint of
𝐴𝐵. He claims that 𝐴𝐵 is the perpendicular
bisector of 𝑋𝑌. What is his error?