Myths about teaching can hold you back
- Year 9
Congruent triangles (RHS)
I can appreciate and use the criteria by which triangles are congruent (RHS).
- Year 9
Congruent triangles (RHS)
I can appreciate and use the criteria by which triangles are congruent (RHS).
Lesson details
Key learning points
- For a right-angled triangle, you need the hypotenuse and one other side length to prove congruence.
- Right-angled triangles, by definition, have a right-angle.
- There is a special relationship between the sides in a right-angled triangle.
Keywords
Hypotenuse - The hypotenuse is the side of a right-angled triangle which is opposite the right angle.
Common misconception
Pupils may make assumptions about diagrams containing a right angle incorrectly.
Remind pupils, that they cannot assume there is a right angle, just because it may look like the two edges are perpendicular to each other.
To help you plan your year 9 maths lesson on: Congruent triangles (RHS), download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 9 maths lesson on: Congruent triangles (RHS), 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 3 maths lessons from the Geometrical properties: similarity and Pythagoras' theorem unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Convert this measurement to centimetres: 23 mm = cm.
Q2.This angle is °.

Q3.Which of these triangles can contain a right angle?
Q4.In all right-angled triangles, what is true about the angles $$a°$$ and $$b°$$?

Q5.In this right-angled triangle, $$a°=$$ °

Q6.Select all the properties of a rhombus.
Assessment exit quiz
6 Questions
Q1.The hypotenuse is the side of a right-angle triangle which is the right angle.
Q2.Which side in this triangle is the hypotenuse?

Q3.Triangle ABC and JKL are congruent by __________.

Q4.Which of the these triangles are congruent to triangle ABC?





Q5.Match each statement to a correct justification to prove that triangle PQS is congruent to triangle PRS by RHS.

PQ = PR -
given on the diagram. PQR is an isosceles triangle.
∠PSQ = ∠PSR = 90° -
given on the diagram. PS is the altitude of the triangle.
PS -
is a common edge to both triangles PQS and PRS
Q6.Can triangles ABD and BCD ever be congruent?
