The Coordinate Plane

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Geometry Honors

• The Coordinate Plane

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The Coordinate Plane
y-axis












QII
QI
x-axis
QIII
QIV
origin
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The Distance Formula
This formula is used to determine the distance
between two points in the coordinate plane.
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Example
Find the length of RT if R(5,2) and T(-4,-1).
d ? (x2 x1)2 (y2 y1)2
Answer
Remember, there could be an exact length and a
decimal approximate length.
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Your Turn
Find the length of QW if Q(5,8) and W(-3,-1).
d ? (x2 x1)2 (y2 y1)2
Answer
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The Midpoint of a Segment
b
a
a b 2
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Example
Find the midpoint of the segment below
-4
-14
Answer
-9
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The Midpoint of a Segment in the Coordinate Plane












?
?
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Example
Find the midpoint of AB if A(5,8) and B(-3,2).
(1,5)
Answer
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Example
The midpoint of AB is M(3,4). One endpoint is
A(-3,-2). Find the coordinate of the other
endpoint B.
(9,10)
Answer
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Definitions
Perpendicular

• forms a right angle at the intersection.
• Symbol ?

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Definitions
Median of a triangle a segment which has one
endpoint at a vertex of the triangle and the
other endpoint at the middle of the opposite side.
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Think
The midpoint of TS is the origin. Point T is
located in Quadrant II. What quadrant contains
point S?
Answer
Quadrant IV
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Quiz 1.1-1.4 on Monday!!!
Please complete the following worksheets
Midpoint Worksheet 2 Midpoint Worksheet 3 SAT
Straight Angles WS Extra Practice Chapter 1