Myths about teaching can hold you back
- Year 10•
- Foundation
Checking and further securing understanding of Pythagoras' theorem
I can use Pythagoras' theorem to calculate the length of a side of a right-angled triangle.
- Year 10•
- Foundation
Checking and further securing understanding of Pythagoras' theorem
I can use Pythagoras' theorem to calculate the length of a side of a right-angled triangle.
Lesson details
Key learning points
- The sum of the squares of the two shorter sides equals the square of the longest side
- The longest side is always opposite the right angle
- The difference between the squares of the longest and known shorter sides is the square of the remaining side
- A calculator can perform these calculations efficiently
- Rounding gives a less accurate answer so there might be times you wish to leave your answer with an operator
Keywords
Hypotenuse - The hypotenuse is the side of a right-angled triangle which is opposite the right angle.
Pythagoras' theorem - Pythagoras’ theorem states that the sum of the squares of the two shorter sides of a right-angled triangle is equal to the square of the hypotenuse.
Common misconception
Misidentifying the hypotenuse.
The hypotenuse is the longest side of a right-angled triangle. It is always opposite the right-angle.
To help you plan your year 10 maths lesson on: Checking and further securing understanding of Pythagoras' theorem, 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 further securing understanding of Pythagoras' theorem, 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 Right-angled trigonometry unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Licence
Prior knowledge starter quiz
6 Questions
Q1.$$14^2=$$
Q2.Izzy has used her calculator to find the square root of 648. Which of these are correct for the given degree of accuracy?

Q3.What type of triangle is this?

Q4.If a square has an edge length of 19 cm, then its area is $$\text{ cm}^2$$.
Q5.A square has an area of 1024$$\text{ cm}^2$$. What is the edge length of the square?
Q6.A square has an area of 1369$$\text{ m}^2$$. What is the perimeter of this square?
Assessment exit quiz
6 Questions
Q1.The hypotenuse is the __________ edge of a right-angled triangle and is always opposite the right angle.
Q2.Match the squares with the correct area.

a -Â
$$169\text{ cm}^2$$
b -Â
$$25\text{ cm}^2$$
c -Â
$$144\text{ cm}^2$$
Q3.Given that Pythagoras’ theorem states that the sum of the squares of the two shorter sides of a right-angled triangle is equal to the square of its longest side (the hypotenuse), a = ...

Q4.Pythagoras' theorem as a formula is $$c^2=a^2+b^2$$, where $$c$$ is the hypotenuse. Which of the following are correct rearrangements of the formula?
Q5.Work out the length of $$x$$.

Q6.Work out the length of $$x$$.
