Question

Which of the given statements are correct when two straight lines intersect?

(i) Adjacent angles are complementary.

(ii) Adjacent angles are supplementary.

(iii) Opposite angles are equal.

(iv) Opposite angles are supplementary.

• A. (i) and (iii) only
• B. (ii) and (iii) only
• C. (i) and (iv) only
• D. (ii) and (iv) only

Answer 1

The correct option is B (ii) and (iii) only

For two straight intersecting lines sum of adjacent angles is ${180}^{\circ }$ and vertically opposite angles are equal.

In the attached figure

$\angle 1+\angle 2=\angle 2+\angle 3=\angle 3+\angle 4=\angle 4+\angle 1={180}^{\circ }$ (Adjacent angles on straight lines)

$\angle 1=\angle 3$ and $\angle 2=\angle 4$ (Opposite angles)

So option $B$ is correct.