Question

When two straight lines intersect, which of the following statements is/are true?

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

Answer 1

Answer: (B), (C)

The correct options are
B Adjacent angles are supplementary.
C Vertically opposite angles are equal.


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