Ch 3.11: Postulates Involving
Lines, Line Segments and Angles
1
A line segment can be extended to any length in either direction.
Through 2 given points, one and only one line can be drawn. (2 points determine a line)
Two lines cannot intersect in more than one point.
2
One and only one circle can be drawn with any given point as a center and the length of any given line segment as a radius.
At a given point on a given line, one and only one perpendicular can be drawn to the line.
From a given point not on a given line, one and only one perpendicular can be drawn to the line.
3
For any 2 distinct points, there is only one positive real number that is called the LENGTH of the line segment joining the 2 points. (Called the DISTANCE POSTULATE)
The shortest path between 2 points is the line segment joining these 2 points.
A line segment has one and only one midpoint.
An angle has one and only one bisector.
4
Converting a conditional statement into the Given/Prove
The IF is the GIVEN
The THEN is the PROVE
Example:
If AB+BC = AC and BC ≅ PR, then AB+PR=AC
GIVEN: PROVE:
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Algebraic Applications:
a. If ABD ≅ DBE, m ABD = 4x ‐10, and m DBE =2x +30, find m ABD and m DBE.
b. If DBC is a right angle, use an answer from part a to find m EBC.
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Homework: pg 128‐129 #1,5,7,9,11,12,15
Due Thrusday: Research PI (3.14) for Pi day!
Write no more than 1 page (double spaced and typed)
Include a reference (not Wikapedia)
Make a poster of your findings about Pi! Be colorful and creative :)
You will present Thursday in class!
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