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Math

Triangle Area Calculator

Find triangle area from a base and its perpendicular height.

Exact method explained belowEditable inputs

Set up your calculation

Runs on your device

SOLUTION

Your result

Let’s calculate.

Use the Calculate button to see your result.

Review the method below for assumptions and conventions.

How to use this tool

  1. Enter base, perpendicular height.
  2. Select Calculate to view the result.
  3. Check the method and assumptions below before using the result.

The method, explained

Area = base × perpendicular height ÷ 2. The height is the shortest distance from the opposite vertex to the base line.

A WORKED EXAMPLE

A base of 10 and perpendicular height of 6 give an area of 30 square units.

What to keep in mind

Height is not generally a slanted side. Both inputs must use the same length unit; zero gives a degenerate area.

Common questions

Can the height fall outside the triangle?

Yes, for some obtuse triangles. It still measures perpendicular distance to the extended base line.

Does this require a right triangle?

No. The base-height formula applies to any triangle when the perpendicular height is known.

Methodology maintained by ClarityKit. How these tools are built and checked.