Area Calculator
Area of any shape.
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Geometry
Triangle Area Calculator
Use base and height, or three sides, to find a triangle’s area.
Triangle area
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Square units.
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How the Triangle Area Calculator Works
The simplest way to find a triangle’s area is half the base times the height (½·b·h) — the height being the perpendicular distance from the base to the opposite corner. If you don’t know the height but know all three side lengths, switch to Heron’s formula, which finds the area from the sides alone.
Heron’s formula uses the semi-perimeter s = (a+b+c)÷2, then area = √(s(s−a)(s−b)(s−c)). Both give the answer in square units.
½ × base × height, or Heron’s √(s(s−a)(s−b)(s−c))
Frequently Asked Questions
How do you find the area of a triangle?
Multiply the base by the perpendicular height and divide by two. If you only know the three sides, use Heron’s formula instead.
What is Heron’s formula?
A way to get a triangle’s area from its three sides: compute s = (a+b+c)÷2, then area = √(s(s−a)(s−b)(s−c)).
What is the height of a triangle?
The perpendicular distance from the base to the opposite vertex — not the slanted side length.
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