Final answer:
The length of the diagonal line in the rhombus can be found using the Pythagorean theorem.
Step-by-step explanation:
A rhombus is a quadrilateral with all four sides of equal length. In the given figure, the rhombus is formed by connecting the points E, F, H, and G. The length of the diagonal line EG is labeled as J and the diagonal line HF is divided into two parts.
To find the length of the diagonal line J, you can use the Pythagorean theorem. Let's assume the length of one side of the rhombus is 'a'. So, the length of the diagonal J can be found using the equation: J = √(a^2 + a^2) = √2a.