Rhombus angles

A corner is a geometric figure formed by two rays (sides of an angle) coming from one point (which is called the vertex of the angle). A plane containing both sides of an angle is divided by an angle into two areas. Each of these areas, combined with the sides of the corner, is called a flat angle (or simply an angle, if this does not cause discrepancies). One of the flat corners (usually the smaller of the two) is sometimes conventionally called internal, and the other external. Points of a flat angle that do not belong to its sides form the inner region of the flat angle.

Rhombus — is called a parallelogram, in which all sides are equal. Since the rhombus is a parallelogram, it has all the properties of a parallelogram.

Since the diagonals of the rhombus are mutually perpendicular, it becomes possible to find the angle of the rhombus, knowing the side and diagonal. In a right-angled triangle formed by the diagonal inside the rhombus, half the diagonals are the legs, any of which can be used, and the rhombus side becomes the hypotenuse. In such a triangle, acute angles will be half the angles of the rhombus, therefore, it will be necessary to use the properties of cosines for the transformations, which ultimately leads to the formula above.