300 u²
1) Let's start by sketching out this:
2) Since a Rhombus have 4 congruent sides, then we can state that 4 sides are 25 units, and we need to find out the other Diagonal (AC)
Applying the Pythagorean Theorem, to Triangle COD
a² =b² +c²
25² = 15² +c²
625 = 225 + c² subtract 225 from both sides
625-225 = c²
400 = c²
√c² =√400
c =20
2.2) Now, we can calculate the area, applying the formula for the area of a rhombus (the product of its diagonals).
[tex]\begin{gathered} A=\frac{D\cdot d}{2} \\ A=\frac{40\cdot30}{2} \\ A=\frac{1200}{2} \\ A\text{ = 600} \end{gathered}[/tex]
3) Hence, the answer is 300 u²
