Area of trapezoids

Target: Use the average of the bases times the height.

Language target: Say “average of the bases.”

Likely miss: Students multiply the two bases and the height.

Ask: Why do we average the bases?

If you see it: Average the bases first, then multiply by the height.

Evidence to listen for: The student can say why the average base is the right length.

Next: Sketch the trapezoid turning into a rectangle of the average base.

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.