Teach Genie
Teach it back in your own words, spot gaps, and remember it better.
Congruent triangles are exactly the same shape and exactly the same size. One triangle can be moved, rotated, or reflected onto the other, but every matching side and angle still agrees.
When we write △ABC≅△DEF\triangle ABC \cong \triangle DEF△ABC≅△DEF, the order tells you the matching vertices: A↔DA \leftrightarrow DA↔D, B↔EB \leftrightarrow EB↔E, and C↔FC \leftrightarrow FC↔F. Getting this order right matters because it tells you which angles and sides correspond.
Question 1
3 marksABCD ABCD\,ABCD is a parallelogram
After proving two triangles are congruent, what equality fact can you use?
Revision notes for Edexcel GCSE Maths Congruent Triangles. Open the guide for explanations and worked examples. Written against the Edexcel GCSE Maths (1MA1) specification, so the content matches what's examinable rather than general Maths background.
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A diagonal ACACAC divides parallelogram ABCDABCDABCD into triangles ABCABCABC and CDACDACDA. Which congruence test proves that the triangles are congruent?
