For all rhombi, the diagonals bisect each other. Therefore, DE and EB are equal. We already know that EB = 9. This means that DE is also 9.
DE = EB ⇒ DE = 9
From the definition of rhombus we know that it has four congruent sides. Therefore, AB and CD are equal. Since we know that AB = 12, the length of DC is also 12.
CD = AB ⇒ CD = 12
Finally, note that â–³ CDE is a right triangle. To find CE we can use the Pythagorean Theorem.
DE^2 + CE^2 = CD^2
We already know that DE = 9 and CD = 12. Let's substitute these values into the above equation and solve for CD.
