Recognise the criteria for the congruence of triangles and solve related problems.
This is level 3; Use your knowledge of congruent triangles to find lengths and angles. The diagrams are not drawn to scale.
When naming congruent triangles the letter order should correspond.
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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/A-level exam paper questions (worked solutions are available for Transum subscribers).
More Geometry including lesson Starters, visual aids, investigations and self-marking exercises.
See the National Curriculum page for links to related online activities and resources.
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 - right-angle, 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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