Polygons on the coordinate plane

Target: Find area from positive side lengths.

Language target: Describe width and height before multiplying.

Likely miss: Students subtract coordinates in the wrong order and get a negative side, or they add coordinates to find area.

Ask: Which subtraction gives the width?

If you see it: Sketch the rectangle and label the positive side lengths.

Evidence to listen for: Area is length times width from the differences of coordinates.

Next: If a side is negative, take the absolute difference.

Homework mark for this device

Until a teacher sets it here, family practice is optional. Stars are an incentive, not a grade. This setting is local. It is not a district roster.

unset optional required incentive

Observable student moves: names both quantities, uses the represented relationship, and revises after feedback. This companion is not a score.