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Area and perimeter - triangles

Calculate the perimeter and area of triangles

3 hand-picked video lessons for this topic, each checked for relevance and clarity, graded by difficulty and labelled by depth. Press play to watch — nothing loads from YouTube until you do.

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Grade 1–3 Core 🇺🇸 US

How to Find the Area and Perimeter of a Triangle | Math with Mr. J

Math with Mr. J 131K views

Clear, worked examples covering both the area and the perimeter of a triangle.

Grade 2–8 Core 🇬🇧 UK

GCSE Maths - How to Find the Area of a Triangle (2026/27 exams)

Cognito 58K views

Up-to-date UK video teaching the base times height rule, plus the higher-tier area formula.

Jump to 0:00Intro & The Two Area Formulas 0:49Area = 0.5 x base x height (Formula 1)0:59Examples using Formula 1 1:58Area = 0.5 x a x b x sin(C) (Formula 2)2:38Examples using Formula 2 3:58Problems Requiring Extra Steps

Grade 1–5 Core 🇬🇧 UK

Area of Shapes - GCSE Maths

1st Class Maths 94K views

Neat UK lesson on triangle area, including grids and finding missing lengths.

Jump to 2:17Area of a triangle 13:21Finding missing lengths