Lesson 7: Represent Polygons on the Coordinate Plane6.GR.3
Stuck? Start here. Read the steps, try the problem, then check your answer.
I can…
I can draw polygons from their vertex coordinates on the coordinate plane, and use coordinates to find side lengths and solve perimeter and area problems.
Key words
vertex — A corner point of a polygon, named by an ordered pair on the coordinate plane.
polygon — A closed figure made of line segments; on the plane you draw it by plotting the vertices and connecting them in order.
perimeter — The total distance around a polygon — the sum of all its side lengths.
distance between vertices — When two vertices share an x- or y-coordinate, the distance between them is the absolute difference of the other coordinates.
scale — What one grid unit stands for in the real situation.
Side length — The distance between two vertices that are joined by a side.
Steps
(-4.5, 3) and (5, 3) share y = 3, so the side between them is horizontal.
Its length is the distance between the x-coordinates: |5 − (−4.5)| = 9.5 units.
(5, 3) and (5, -3.75) share x = 5, so that side is vertical: |3 − (−3.75)| = 6.75 units.
Try it
A rectangle has vertices (-3, 2), (4, 2), (4, -3), (-3, -3). What is its perimeter?