Question

In the diagram, m∠ECA = 120.

m∠BCD = ___

A:120
B:90
C:60
D:180

Answer 1

A.

The angles are vertical pairs, which means they are always congruent.

Answer 2

Answer: The correct option is (A) 120°.

Step-by-step explanation: In the given figure, the lines AD and EB intersect each other at the point 'C'.

And, m∠ECA = 120°.

We are to find the measure of ∠BCD, i.e., m∠BCD.

We know that the measures of two vertically opposite angles are equal.

Since ∠ECA and ∠BCD are vertically opposite angles, so their measures must be equal.

That is,

m∠ECA = m∠BCD.

Since, m∠ECA = 120°.

Therefore, m∠BCD = 120°.

Thus, (A) is the correct option.