The Coordinate Challenge of Elana and Matt
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Challenges

Elana and Matt have decided to compete in a "challenge" to see whose powers of observation are the strongest in relation to figures drawn on a coordinate plane.

You will be acting as the judge (and supreme keeper of the correct answer) during this challenge. Your task is to prepare a proof showing the correct result for each question and to keep track of Elana's and Matt's scores to determine the winner. 

Let the challenge begin! 

  Figure Elana's prediction Matt's prediction
1 Quadrilateral A(1,2), B(2,5), C(5,7) and D(4,4) ABCD is a rhombus ABCD is a parallelogram, but not a rhombus
2 Triangle A(1,1), B(4,4), C(7,2) ABC is a right triangle ABC is not a right triangle
3 Quadrilateral A(3,1), B(5,6), C(7,6), D(10,2) The diagonals are not perpendicular. The diagonals are perpendicular.
4 Quadrilateral A(0,-2), B(9,1), C(4,6), D(1,5) ABCD is an isosceles trapezoid ABCD is a trapezoid, but not isosceles
5 Line segment A(1,5) B(2,3) and
                            line segment C(4,4) D(-2,1)
The segments are perpendicular The segments are not perpendicular.

 

Score Card
Problem Elana Matt
1    
2    
3    
4    
5    

The winner is ________________.

 

Note to teacher:  There are many variations on this activity.
1.  You can use this activity as it is presented with Matt and Elana.

2.  You can choose two students to play the parts of Matt and Elana.  Draw the five figures on graph paper and let the two students "see" the graphs (no touching).  Then have each student record on a piece of paper what he/she "observed" regarding the figure in relation to the specifications listed above (is it a rhombus, are the lines perpendicular, etc).  Then have the class (individually or in groups) prove what the actual answers are and score the two students.

3.  You can have everyone take on the parts of Matt and Elana.  Show the graphs to the entire class and ask each student separately to write down their "observed" truth.  Have the class (individually or in groups) prove each "truth".

4.  Have each group of students prove a different question and then pool answers.

5.  Have one class challenge another class.