If ℓ1 is parallel to ℓ2 in the figure above, which of the following ex

Hi All,

This question is built around a few essential 'line rules' that you need to know for Test Day:

1) When parallel lines are crossed by a third line, the corresponding angles are EQUAL.
2) When two lines 'criss-cross', opposite angles are EQUAL
3) The sum of the angles on one side of a line totals 180 degrees.

In this prompt, we're told that L1 and L2 are parallel, which means that....

Angle A = Angle C
Angle B = Angle D

Since the two non-parallel lines criss-cross....

Angle E = the angle directly across the line from it.

Using this information, you can deduce that the first two of the three Roman Numerals CANNOT total 180 degrees (because there is missing 'angle space' between the angles). Based on the answer choices, since those two options don't total 180 degrees, there's only one answer that could be correct...

Final Answer:

You can prove that Roman Numeral 3 totals 180 degrees though (using the three rules I listed above).

GMAT assassins aren't born, they're made
Rich