Myths about teaching can hold you back
- Year 7
Using the formula for the area of a triangle
I can use the formula for the area of a triangle to calculate missing side lengths.
- Year 7
Using the formula for the area of a triangle
I can use the formula for the area of a triangle to calculate missing side lengths.
Lesson details
Key learning points
- 0.5 x base x perpendicular height can be used to find the area of any triangle.
- Missing sides can be found if the area is known.
Keywords
Base - The base is the side which is perpendicular to the height.
Perpendicular height - The perpendicular height is the perpendicular distance from the base to the opposite vertex.
Common misconception
Pupils may think the height of the triangle is the slanted height rather than perpendicular.
The base and height to be used must be perpendicular (at a right angle) to each other.
To help you plan your year 7 maths lesson on: Using the formula for the area of a triangle, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your year 7 maths lesson on: Using the formula for the area of a triangle, 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 Perimeter and area unit, dive into the full secondary maths curriculum, or learn more about lesson planning.
Equipment
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Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.The perpendicular is the perpendicular distance from the base to the opposite vertex.
Q2.True or false? You can calculate the area of this triangle.

Q3.True or false? We can calculate the area of this triangle.

Q4.Calculate the area of a triangle with a base of 13 cm and a perpendicular height of 3 cm (you do not need to give the units).
Q5.Two triangles can always be placed together to create a parallelogram.
Q6.Which of these is the correct way to calculate the area of this triangle?

Assessment exit quiz
6 Questions
Q1.The base and height of this triangle measure:

Q2.Select the correct expression for the area of the triangle.

Q3.Select the correct expression for the area of the triangle.

Q4.Calculate the missing side length.

Q5.Calculate the missing side length.

Q6.Calculate the missing side length.
