Congruent TrianglesRecognise the criteria for the congruence of triangles and solve related problems. 
This is level 1; Determining whether two triangles are congruent and finding the reason. The diagrams are not drawn to scale.
For each pair of triangles select the correct description of congruency.


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Pairs  The classic pairs game with simple congruent shapes.
Level 1  Determining whether two triangles are congruent and finding the reason
Level 2  Further questions on recognising congruency ordered randomly
Level 3  Use your knowledge of congruent triangles to find lengths and angles
Similar Shapes  Similarity is a related concept.
Exam Style Questions  A collection of problems in the style of GCSE or IB/Alevel exam paper questions (worked solutions are available for Transum subscribers).
More Geometry including lesson Starters, visual aids, investigations and selfmarking exercises.
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The following conditions guarantee congruence:
SSS  Given the lengths of all three sides.
SAS  Given two sides and the included angle.
ASA or AAS  Given two angles and any side.
The following is a set of conditions that does not guarantee congruence:
ASS  Given two sides and an angle that is not included between them. However congruence could be confirmed if the angle is a right angle (RHS  rightangle, hypotenuse, side) or an obtuse angle or if the side not adjacent to the angle is longer than the side that is adjacent.
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