The sides of a rhombus ABCD measure 2 cm each, and the difference between two of its angles is \(90^{\circ}\). Then the area of the rhombus is:
Show Hint
A rhombus has only two distinct angles that add up to 180 degrees; use their given difference to find each one, then apply Area = side squared times sine of the angle.
Step 1: Recall the angle property of a rhombus.
A rhombus has only two distinct interior angles, since opposite angles are equal and any two adjacent angles are supplementary (they add up to \(180^{\circ}\)). So if one angle is \(\theta\), the angle next to it is \(180^{\circ} - \theta\).
Step 2: Use the given angle difference to find \(\theta\).
The difference between the two distinct angles is \(90^{\circ}\).
\[ (180^{\circ} - \theta) - \theta = 90^{\circ} \]
\[ 180^{\circ} - 2\theta = 90^{\circ} \]
\[ 2\theta = 90^{\circ} \]
\[ \theta = 45^{\circ} \]
So the two angles of the rhombus are \(45^{\circ}\) and \(135^{\circ}\).
Step 3: Recall the area formula for a rhombus in terms of side and angle.
For a rhombus with side \(a\) and one interior angle \(\theta\), the area is
\[ \text{Area} = a^2 \sin\theta \]
This comes from splitting the rhombus into two triangles along a diagonal and using the triangle area formula \(\frac{1}{2}ab\sin\theta\), since both sides meeting at that angle equal \(a\).
Step 4: Substitute the known values.
Here \(a = 2\) and \(\theta = 45^{\circ}\) (using \(135^{\circ}\) instead gives the same result, since \(\sin 135^{\circ} = \sin 45^{\circ}\)).
\[ \text{Area} = 2^2 \times \sin 45^{\circ} = 4 \times \frac{\sqrt{2}}{2} = 2\sqrt{2} \]
Step 5: Rule out the other options.
Option (A) would come from forgetting to square the side length. Options (C) and (D) would come from using the wrong angle or a slip while simplifying \(4 \times \frac{\sqrt{2}}{2}\).
Final Answer:
The area of the rhombus is \(2\sqrt{2}\) sq cm.
\[ \boxed{2\sqrt{2} \text{ sq cm}} \]