In each of the following figures, two lines AB and CD are cut by a transversal EF. In each case, find whether AB || CD or not. Give reasons in support of your answer.

(i)

(ii)

(iii)

(iv)

(v)

The sum of all the angles at a point is

1. 0°
2. 90°
3. 180°
4. 360°

Vertically opposite angles

1. are complementary
2. are supplementary
3. are equal
4. form a linear pair

When two parallel lines are cut by a transversal, then the co-interior angles are

1. equal
2. supplementary
3. complementary
4. always unequal