Question

which angle is complementary to \\( \angle c d a \\)?

Explanation:

Step1: Recall the definition of complementary angles

Complementary angles are two angles whose sum is \(90^{\circ}\).

Step2: Analyze the given figure

Since the angle formed at point \(D\) (the right - angled one) is \(90^{\circ}\), and \(\angle CDA+\angle BDC = 90^{\circ}\) (because they make up the right - angle at \(D\)).

Answer:

\(\angle BDC\)