Checking and securing understanding of congruent triangles (ASA)
I can understand and use the criteria by which triangles are congruent (ASA).
Checking and securing understanding of congruent triangles (ASA)
I can understand and use the criteria by which triangles are congruent (ASA).
These resources will be removed by end of Summer Term 2025.
Lesson details
Key learning points
- By knowing two angles and the length between them in the triangle and image, you can prove congruence.
- The angle pairs must be identical.
- This rule is derived from the SAS criteria for congruence.
Keywords
Congruent - If one shape can fit exactly on top of another using rotation, reflection or translation, then the shapes are congruent.
Similar - Two shapes are similar if the only difference between them is their size. Their side lengths are in the same proportions.
Common misconception
Pupils may struggle to spot congruent triangles when the two angles are not at the ends of the known side.
Encourage pupils to add any further information to diagrams, like the third angle, before starting to prove congruence.
To help you plan your year 10 maths lesson on: Checking and securing understanding of congruent triangles (ASA), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 10 maths lesson on: Checking and securing understanding of congruent triangles (ASA), download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 maths lessons from the Similarity unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Starter quiz
6 Questions




Exit quiz
6 Questions


$$w$$ -
7.2 cm
$$y$$ -
8.3 cm
$$z$$ -
5.8 cm

