Consider the following statements:

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

Of these statements

#### Options

(i) and (ii) are correct

(ii) and (iii) are correct

(i) and (iv) are correct

(ii) and (iv) are correct

#### Solution

Let us draw the following diagram showing two straight lines AD and BC intersecting each other at a point O.

Now, let us consider each statement one by one:

(i) When two lines intersect adjacent angles are complementary.

This statement is __incorrect__

Explanation:

As the adjacent angles form a linear pair and they are supplementary.

(ii) When two lines intersect adjacent angles are supplementary.

This statement is** correct.**

Explanation:

As the adjacent angles form a linear pair and they are supplementary.

(iii) When two lines intersect opposite angles are equal.

This statement is __correct.__

Explanation:

As the vertically opposite angles are equal.

(iv) When two lines intersect opposite angles are supplementary.

This statement is** incorrect.**

Explanation:

As the vertically opposite angles are equal

Thus, out of all, (ii) and (iii) are correct.