Question

When two straight lines intersect, which of the following statement(s) is/are true?

• A. Adjacent angles are complementary.
• B. Adjacent angles are supplementary.
• C. Opposite angles are equal.
• D. Opposite angles are supplementary.

Answer 1

Answer: (B), (C)

The correct options are
B

Adjacent angles are supplementary.

C

Opposite angles are equal.

When two straight lines intersect, then the adjacent angles are supplementary and the opposite angles are equal. In the given diagram, two straight lines intersect.
$\angle 1$ and $\angle 3$ are opposite angles and are equal, while $\angle 1$ and $\angle 2$ are adjacent and supplementary.