Use the formula: Area = 1/2 × base × height
Measure the base of the triangle
Measure the perpendicular height from the base to the opposite vertex
Multiply the base by the height
Divide the result by 2
If you know all three sides, use Heron’s formula: Area = √[s(s – a)(s – b)(s – c)]
Compute s using: s = (a + b + c) / 2
Substitute the side lengths into the formula
If you know two sides and the included angle, use: Area = 1/2 × a × b × sin(C)