Parallelogram diagonal calculator

Diagonal in geometry, a line segment connecting two non-adjacent vertices of a polygon or polyhedron. The diagonal of a polygon is a line segment connecting its two vertices that do not lie on one side.

Parallelogram — is a quadrangle in which the opposite sides are pairwise parallel, that is, they lie on parallel lines. Particular cases of a parallelogram are a rectangle, a square, and a rhombus.

According to the cosine theorem, the side of the triangle to the second degree is equal to the sum of the squares of its two other sides and their double product by the cosine of the angle between them. Since any diagonal of a parallelogram divides it into two congruent triangles, you can calculate the diagonal by knowing the sides of the parallelogram and the angle between them. Keep in mind that the angle and the diagonal must be in the same triangle, otherwise you need to calculate the necessary angle, taking away the known from 180 degrees by the principle of additional angles.