Question

Two lines AB and EF are parallel to a third line CD. Then AB and EF are

• A. Parallel
• B. Perpendicular
• C. Intersect at 450

Answer 1

The correct option is A Parallel

Shown below are two lines, AB and EF, which are parallel to a common line CD. Let K be the transversal passing through the three lines.

We know that if a transversal intersects two parallel lines then the corresponding angles are equal.

as AB || CD, $\angle$1 = $\angle$2 (corresponding angles)

as CD || EF, $\angle$2 = $\angle$3 (corresponding angles)

Hence, $\angle$1 = $\angle$3

Therefore, AB is parallel to EF.