Checking and securing understanding of similar triangles
I can recognise that similar shapes have sides in proportion to each other but angle sizes are preserved.
Checking and securing understanding of similar triangles
I can recognise that similar shapes have sides in proportion to each other but angle sizes are preserved.
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Lesson details
Key learning points
- An enlargement means a change in size.
- The lengths of the lines may change when enlarged.
- The angles inside an object do not change when enlarged.
- When an object is enlarged, the image is similar.
Keywords
Similar - Two shapes are similar if the only difference between them is their size. Their side lengths are in the same proportions.
Enlargement - Enlargement is a transformation that causes a change of size.
Scale factor - Scale factor is the multiplier between similar shapes that describes how large one shape is compared to the other.
Common misconception
You need to know all the lengths or all of the angles in a pair of triangles to know that they are similar.
Remind pupils that they do not necessarily need to know all of the length and angles to determine whether two triangles are congruent, so they don't all need to be known to determine similarity.
To help you plan your year 9 maths lesson on: Checking and securing understanding of similar triangles, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 9 maths lesson on: Checking and securing understanding of similar triangles, 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.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 3 maths lessons from the Trigonometry unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Lesson video
Starter quiz
6 Questions
< 90ᵒ
90ᵒ
>90ᵒ and <180ᵒ
>180ᵒ
180ᵒ
Exit quiz
6 Questions
