Work out area of triangle using sine instantly with clear inputs, formula shown and shareable results.
When two sides and the angle between them are known, the area is ½ab·sin C. The perpendicular height onto side a is b·sin C, which is exactly what turns the familiar ½ × base × height into this form.
Area (SAS)
Area = ½ · a · b · sin C
Law of cosines
c² = a² + b² − 2ab·cos C
½ × 8 × 10 × 0.5 = 20 square units, since sin 30° = 0.5 exactly.
Yes. Using a non-included angle gives the wrong area; for that case solve the triangle first.