Creating Congruent Triangles
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Under what conditions are triangles congruent?

 

Materials:  rulers and protractors
(students may work alone or in groups)

1. Draw a triangle of any size and shape and label it ABC.
 
2.  Using the ruler and protractor, measure and record the angles and sides of the triangle.  Remember that there are 180 degrees in the sum of the angles of a triangle.
 
3.  Draw triangle DOG where DO = AB, m<D = m<A, and m<O = m<B.
 
4.  Measure and record the remaining angles of triangle DOG.
 
5. Are triangles ABC and DOG congruent?
 
6.   Is it possible to draw triangle DOG so that it is NOT congruent to triangle ABC?
 
7.  Draw triangle KIT where KI = AB, m<K = m<A, and m<T = m<C.
 
8.  Measure and record the remaining angles of triangle KIT.
 
9.   Are triangles ABC and KIT congruent?
 
10.  Is it possible to draw triangle KIT so that it is NOT congruent to triangle ABC?
 
11. Discuss your findings from this activity.