Explore the triangle area formula, its derivation, and practical examples to master this essential geometric concept effortlessly.

Learn how to calculate the areas of rectangle, triangle, and circle in Excel for a single cell or range of cells usin this formula.

The outside edge of a shape is known as the perimeter. Learn how to work out the perimeter of a 2D shape with this Year 4 article from BBC Bitesize.

Zach and Kayla talk through their calculations to find the missing lengths, then add them together to find the perimeter. Second, they calculate the missing angles from inside a rectilinear shape.