If two lines intersect at a point, then the vertically opposite angles are always equal.

Fill in the blanks:

(i) If two angles are complementary, then the sum of their measures is _______.

(ii) If two angles are supplementary, then the sum of their measures is _______.

(iii) Two angles forming a linear pair are _______.

(iv) If two adjacent angles are supplementary, they form a _______.

(v) If two lines intersect at a point, then the vertically opposite angles are always _______.

(vi) If two lines intersect at a point, and if one pair of vertically opposite angles are acute angles, then the other pair of vertically opposite angles are _______.

If two lines intersect at a point and if one pair of vertically opposite angles are acute, then the other pair of vertically opposite angles are.

If two lines intersect each other, then the vertically opposite angles are ……….