What this calculator does
Triangle area can be calculated from base and height, from three sides, or from two sides and the included angle.
Base and heightA = 1/2 × base × height.
Three sidesUse Heron’s formula.
Right triangleArea is one half of the product of the legs.
For classroom work, check the required rounding rules and whether angles are in degrees or radians. This page uses degrees.
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