Geometry
Triangle area
- where
- area (m²)
- base (m)
- perpendicular height (m)
Explain this equation
This finds the area of a triangle, such as a gable, a raked infill panel or a triangular piece of paving.
b is the base, the side you choose to measure along. h is the perpendicular height, the square distance from the base line up to the opposite corner. A is the area in m².
Any triangle is exactly half of the rectangle or parallelogram built on the same base and height, which is why the product b × h is divided by 2. The shape of the sloping sides does not matter as long as h is measured square to the base.
A 4 m base with a 3 m perpendicular height gives 6 m², half of a 4 × 3 rectangle. Doubling either the base or the height doubles the area.
Watch out: h is not the length of a sloping side. Using the sloping side overstates the area.
Calculate a triangle using its base and perpendicular height.
Enter your values to see the result.
Good to know
The height must be at right angles to the base, not the sloping side.
Sources
- Geometry / arithmetic
Estimates are not design approval or British Standards compliance checks. Structural arch, retaining-wall, wind, foundation, lintel and masonry-capacity design are not performed. Use the project engineer’s specification.