The quadrilateral has eight parts: four sides and four angles.
This is another check of a triangle.Ģ.3.11 If \(\,b\ \cos\ A = a\ \cos\ B\, \), show that the triangle \(\triangle\,ABC \) is isosceles.Ģ.3.12 Let \(ABCD \) be a quadrilateral which completely contains its two diagonals.
\).) Notice that this formula provides another way of solving a triangle in Case 3 (two sides and the included angle).Ģ.3.10 For any triangle \(\triangle\,ABC \), show that \(\ c = b\ \cos\ A + a\ \cos\ B\, \).
