Opposite angles of a Quadrilateral ABCD are equal. If AB = 4cm, find the length of CD. [1]a) 4 cm b) 3 cmc) 5 cm d) 2 cm

1. Break Down the Problem

We have a quadrilateral ABCD where opposite angles are equal. This suggests that ABCD may have properties akin to a parallelogram. We are given that AB = 4 cm, and we need to find the length of CD.

2. Relevant Concepts

In a quadrilateral where opposite angles are equal, it follows that opposite sides are also equal. The properties of such quadrilaterals can simplify the problem.

3. Analysis and Detail

Since opposite sides in this type of quadrilateral (specifically parallelograms) are equal, we have: $AB = CD$ Given: $AB = 4 \, \text{cm}$ Therefore: $CD = 4 \, \text{cm}$

4. Verify and Summarize

We've established using the property of the quadrilateral that the length of side CD must be equal to the length of side AB.

Final Answer

The length of CD is 4 cm. Thus, the correct answer is a) 4 cm.