Title: Congruent Trapezoids
Problem: The figure shows a trapezoid composed of three
congruent isosceles right triangles. Cut it into four congruent trapezoids.
Math Topic/Concept: Congruence
Materials: pencil, handout
Classroom Use: (Introductory/Developmental/Evaluation)
Classroom use comments: This could be a take home, challenge problem or a problem used in a problem-solving unit.
Grade: Geometry; 10th grade
Grade Cluster: (EarlyElem/LateElem/MS-Jr.High/EarlyHS/LateHS)
Illinois Goal: 9.A.4b
Standard: Geometry, Problem Solving, Reasoning and Proof
Applied? (1-4): Level 1. There are no real world elements, but it is still mathematically interesting.
Source: Calendar. Mathematics Teacher. v93 n4 p312-16 Apr 2000.
Answer: This is a rough sketch of the solution. The teacher
must verify the student answers using 
this
as a guide.
Strategies Listed: Use logic and trial & error
Solution: Students must use the definitions of congruent, isosceles right triangle and trapezoid to solve the problem.
Other solution methods (if any): none
Intended rubric or assessment method: 10 points total.
One point for each congruent trapezoid
Two points for showing trial and error attempts
Two points for describing the procedure they used to arrive at their answer.
Two points for stating the reason as to why the trapezoids they drew are congruent.
Write-up submitted by: Andrea Gillett
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