Answer:
The area of the rhombus is 25.83 cm².
Step-by-step explanation:
The area of a rhombus is given by:

Where:
d₁: is one diagonal
d₂: is the other diagonal = d₁ + 4 cm
We know that one side length of the rhombus is equal to d₁. We can imagine a right triangle inside the rhombus, with the following dimensions:
h: hypotenuse of the right triangle
a: one side of the right triangle
b: is the other side of the right triangle
From the above we know that:
h = d₁

We can find d₁ with Pitagoras:


By solving the above quadratic equation for d₁ and taking the positive solution we have:
So, d₂ is:

Now, we can find the area:

Therefore, the area of the rhombus is 25.83 cm².
I hope it helps you!