Article in English: The height of a triangle can be found if you have 2 sides and the angle in between them, or all three sides. We'll call the sides of the triangle a, b, and c, and the angles, A, B, and C.  If you have all three sides, you'll use Heron's formula, and the formula for the area of a triangle. If you have two sides and an angle, you'll use the formula for the area given two angles and a side. A = 1/2ab(sin C). Heron's formula has two parts. First, you must find the variable s, which is equal to half of the perimeter of the triangle. This is done with this formula: s = (a+b+c)/2. Replace area in the formula with its equivalent in the area of a triangle formula: 1/2bh. This gives you a formula that looks like 1/2bh = 1/2ab(sin C). This can be simplified to h = a(sin C), thereby eliminating one of the side variables.

Summary in Indonesian:
Tentukan variabel yang diketahui. Gunakan rumus Heron jika Anda mengetahui panjang ketiga sudut segitiga. Gunakan rumus luas segitiga dari dua sisi dan satu sudut, jika yang diketahui adalah satu sisi dan satu sudut segitiga.