Polygon Classification in the
Coordinate Plane
Jen Kershaw
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Printed: October 6, 2013
AUTHOR
Jen Kershaw
www.ck12.org
C ONCEPT
Concept 1. Polygon Classification in the Coordinate Plane
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Polygon Classification in
the Coordinate Plane
Here you’ll learn to graph geometric figures given coordinates of vertices.
Remember Josh from the last Concept?
Well, Josh created a different map to send to his pen pal in New Zealand. On his map, he placed four different things.
He placed his home, the skatepark, the library and his friend Sarah’s house.
Here are the coordinates of Josh’s map.
Home (-3,1)
Skatepark (-3,5)
Library (2,5)
Sarah’s house (2,1)
Josh plotted these points on a coordinate grid and then drew lines connecting the points.
What shape figure united these points?
Do you know?
This Concept is about graphing geometric figures given coordinates of vertices. You will be able to identify
the figure created on Josh’s map by the end of the Concept.
Guidance
Now that you have learned how to graph points in all four quadrants, you can look at graphing lines and figures on
the coordinate grid. If you have the coordinates of each vertex of a figure, you can easily graph it on the coordinate
grid. Remember that the coordinates are the ordered pairs of each point. The coordinates let you know where to
graph each point.
Graph a figure with the coordinates A(−4, 3) B(2, 3) C(2, −1) D(−4, −1). When finished, name the figure that has
been drawn on the grid.
To start with, we plot each point on the coordinate grid and then we connect the lines. This will give us a
geometric figure.
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Now that we have it graphed, you can use what you have already learned about geometric figures to name the
figure.
This is a rectangle.
You can graph any geometric figure on the coordinate grid as long as you have been given the coordinates.
First, plot each point.
Then, connect the points to form a figure.
Finally, use what you have learned to name the figure drawn.
Let’s practice one more.
Graph and name the following figure with these coordinates D(1, 3) E(5, 3) F(7, −1) G(1, −1)
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Concept 1. Polygon Classification in the Coordinate Plane
Here we have graphed a four sided figure with one pair of parallel sides. This is a trapezoid.
Now it’s time for you to try a few on your own. Graph each figure and then name the figure.
Example A
(0, 2)(2, 0)(0, −3)
Solution: Triangle
Example B
(−1, −3)(−5, −3)(−7, 1)(−1, 1)
Solution: Trapezoid
Example C
(3, 3)(0, 3)(0, 0)(3, 0)
Solution: Square
Here is the original problem once again.
Well, Josh created a different map to send to his pen pal in New Zealand. On his map, he placed four different things.
He placed his home, the skatepark, the library and his friend Sarah’s house.
Here are the coordinates of Josh’s map.
Home (-3,1)
Skatepark (-3,5)
Library (2,5)
Sarah’s house (2,1)
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Josh plotted these points on a coordinate grid and then drew lines connecting the points.
What shape figure united these points?
Do you know?
When you plot these points on the coordinate grid and connect the lines, you will see that a rectangle is the shape
formed by the lines and points.
This is our answer.
Vocabulary
Here are the vocabulary words in this Concept.
Quadrants
the four sections of a coordinate grid
Origin
the place where the x and y axis’ meet at (0, 0)
Ordered Pair
the x and y values used to locate points on a coordinate grid (x, y)
x axis
the horizontal axis on the coordinate grid
y axis
the vertical axis on the coordinate grid
Coordinates
the x and y values of an ordered pair
Guided Practice
Here is one for you to try on your own.
What is the name of the figure created by graphing the following vertices?
(-4,6)
(4,6)
(0,-6)
(0,6)
Answer
If you graph all four of these points and connect the vertices, then you will see that there is a trapezoid that is created
on the coordinate grid.
Video Review
Here is a video for review.
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Concept 1. Polygon Classification in the Coordinate Plane
MEDIA
Click image to the left for more content.
James Sousa, Plotting Points on the Coordinate Plane
Practice
Directions: Graph each figure using the vertices. Then name the graphed figure.
1.
amp; A(−2, 2)
amp; B(2, 2)
amp;C(2, −2)
amp; D(−2, −2)
2.
amp; D(−4, 3)
amp; E(−1, 1)
amp; F(−4, 1)
3. (1, 1)(2, 3)(4, 1)
4. (−1, 3)(−5, 3)(−1, 0)(−5, 0)
5. (0, 5)(3, 5)(0, 9)(3, 9)
6. (0, 6)(2, 6)(0, 10)(2, 10)
7. (−3, 6)(6, 0)(9, 0)
8. (−1, 6)(−1, 8)(−9, 6)(−9, 8)
9. (0, −8)(1, −5)(5, −5)(4, −8)
10. (12, 0)(12, 6)(7, 0)
Directions: For 11 - 15 Draw five of your own figures on a coordinate grid. Write out each set of coordinates and
work with a partner to identify each figure using only the coordinates.
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