Math
Triangle geometry
Calculate triangle area and perimeter from a base, perpendicular height and three sides.
Calculators / Math / Triangle altitude from area
Triangle altitude from area calculator
Recover a triangle’s perpendicular height from its area and a chosen base.
On this page
Perpendicular altitude5
Equal-area rectangle height2.5
Calculator controls
How to calculate
Recover a triangle’s perpendicular height from its area and a chosen base.
Perpendicular altitude =
2*area/baseEqual-area rectangle height =
area/baseWorked example
- Chosen base: 12
- Triangle area: 30
- Perpendicular altitude: 5
- Equal-area rectangle height: 2.5
Assumptions and limits
The height is perpendicular to the chosen base, not a sloping edge. Area and base must use compatible squared and linear units.
Results are rounded for display; calculations use unrounded values. Read our calculation methodology.
Understanding the result
Recover a triangle’s perpendicular height from its area and a chosen base. Place a matching triangle beside the first: together they form a parallelogram with twice the triangle area.
When this tool is useful
Place a matching triangle beside the first: together they form a parallelogram with twice the triangle area.
Understanding your inputs
| Input | Example |
|---|---|
Chosen base base | 12 |
Triangle area area | 30 |
Frequently asked questions
What assumptions should I check?
The height is perpendicular to the chosen base, not a sloping edge. Area and base must use compatible squared and linear units.
How can I check the result?
Start with the labelled example. Keep units consistent, calculate without intermediate rounding and change one input at a time. The diagram explains the model; the result table supplies the numerical answer.