Area of a triangle

Triangle area formulas

Designations: a, b, c – sides of a triangle;

r - radius of the inscribed circle, R- radius of the circumscribed circle;

h_a, h_b, h_c – heights dropped to the sides a, b, c, respectively;

p – semiperimeter,

The area of a triangle given the side a and the height h_a dropped to the side a

The area of a triangle given two sides a and b, and the angle γ between them

Area of a right triangle

Area of a triangle given three sides and semiperimeter (Heron's formula)

Area of a triangle given the radius of the inscribed circle and the semiperimeter

The area of a triangle given the radius of the circumscribed circle and three sides

Area of a triangle given three heights

Area of an equilateral triangle with side a

Area of an equilateral triangle given the radius of the inscribed circle r

The area of an equilateral triangle given the radius of the circumscribed circle R

For an equilateral triangle