Big Idea:

Big Idea 2

A polygon is categorized by the length and direction of its line segments on the coordinate plane.

1 week

Evidence of Understanding

  • analyze and describe characteristics of polygons on the coordinate plane
    • calculate the length and direction of sides of a polygon using the slope and distance formulas
    • determine the length or direction of a line segment in relation to the sides of a polygon (including an altitude, perpendicular bisector, etc.)
    • compare polygons using the length or direction of their sides, angle, or diagonals to describe how they are similar, congruent, or neither
    • calculate and compare the perimeter of various polygons on the coordinate plane
      • use the distance formula, Pythagorean Theorem, etc.
    • calculate areas of triangles or rectangles on the coordinate plane
      • identify points that are needed to calculate area of triangles and rectangles
      • explore when area changes or stays the same based on the lengths being used (Example: height of a triangle)
    • transform polygons and describe the relationship between a pre-image and its image under a transformation on the coordinate plane
      • apply and justify the ratio of the scale factor on perimeter and area
  • prove geometric relationships on the coordinate plane
    • prove two figures are congruent or similar in the coordinate plane
      • use similarity relationships to determine ratios between segments
    • classify a polygon using characteristics of its sides, angles, and diagonals
      • determine what information is sufficient to prove the classification of a triangle/ quadrilateral
      • given a specified polygon, find coordinates of points or lengths or directions of line segments that make the classification valid

Develop conceptual understanding:

perimeter, area

Supporting terms to communicate:

slope, distance, length, parallel, perpendicular, partition, dilation, equilateral, right, isosceles, quadrilateral, rectangle, square, rhombus, parallelogram, diagonals, bisect, midpoint, perpendicular bisector, height, base

Core Resource

A core resource supports multiple days of instruction.

  • Proving Polygons
    This Core Resource is where students use tools related to the coordinate plane to classify polygons and prove polygons congruent or similar to each other.
    Resource:
    Proving Polygons

    This Core Resource is where students use tools related to the coordinate plane to classify polygons and prove polygons congruent or similar to each other.

    All Resources From:
Instructional Routine: Contemplate then Calculate
These tasks are embedded within the instructional routine called Contemplate then Calculate.
Instructional Routine: Sharing Skepticism

The primary goal of this instructional routine is to support students in constructing and critiquing mathematical arguments.