# Coordinate Plane Polygons

Polygon: a 2 dimensional plane figure with at least three straight sides and angles where none of the sides cross and the figure is closed.

Coordinate points: The coordinates of a point are a pair of numbers that define its exact location on a two-dimensional plane. The coordinate plane has two axes at right angles to each other, called the x and y axis. The coordinates of a given point represent how far along each axis the point is located.

The two numbers in parentheses are the x and y coordinate of the point. The first number (x) specifies how far along the x (horizontal) axis the point is. The second is the y coordinate and specifies how far up or down the y axis to go. It is called an ordered pair because the order of the two numbers matters - the first is always the x (horizontal) coordinate. (4,2) identifies a location 4 to the right of the origin and 2 up from the x axis.

Another way to think of coordinate point locations is using the metaphor of a tall building with multi elevators. First you walk along the lobby of the building looking for your elevator which is numbered -2, -1, 0, 1, 2  and so on. You enter the elevator (this is your “x” coordinate) and then you push the button representing how high or low you want to go in the building (the floor is your “y” coordinate). Students often mix up the y and x axis and this is a way to ensure that x comes before y; you would never enter your floor first and then pick an elevator.

Challenge: First, draw as many different polygons as possible with every vertex at a lattice point (were a horizontal and vertical line intersect). Second, on the other page, list the coordinate points clockwise in order of each vertex.

When a computer creates a polygon it must identify each vertex and must end on the same vertex with which it started. For example, if the computer creates a triangle, and identifies (1,2) as the starting point, then (3,5), and finally (4,0), it must identify a fourth coordinate point which is the original (1,2) in order to close (complete) the triangle. So a quadrilateral must identifyfy five coordinate points for the four vertices; a pentagon, six points, and so on

Record the coordinate points on the pdf called Coordinate Plane Polygons 1st Quadrant (1st and 2nd grade) or 4 Quadrants (3-6th grade), next to the corresponding polygon. If the polygon you create has 23 sides, cross out “20” and write “23” and call it tri-icosagon.

AttachmentSize
Polygon_Images_Buildings_and_Signs.pdf1.9 MB
Coordinate_Plane_Polygon_Names_and_Recordation.pdf56.38 KB