Cracking The SAT Premium

Note:   Figure  not drawn   to  scale.

In  the figure  above,  l 2     ||  l 3 .   Which   of  the following   could   be  false?

A) a    =   e

B) b    +   e   =   180

C) l 1   l 4

D) c    =   d

Here’s How to Crack It

Start by marking l 2 and l 3 as parallel lines. Next, because you’re looking for what could be false, consider

each answer choice and use POE. For (A), if l 2 and l 3 are parallel, then l 4 transects both lines and creates

sets of equal angles. All small angles around l 4 which are formed by l 2 or l 3 are equal, so a must be equal

to e; eliminate (A). Choice (B) is based on the same set of intersecting lines; because l 2 and l 3 are parallel

and l 4 transects both lines, then any big angle plus any small angle equals 180°. Therefore, (B) must be

true; eliminate it. For (C), you don’t know the value of any angles, so you cannot determine if these lines
are perpendicular. Since (C) could be false, choose (C). Choice (D) must be true because opposite angles
created by two lines are always equal.

Converting Degrees to Radians

Some geometry questions will ask you to convert an angle measurement from degrees to radians. While
this may sound scary, doing this conversion requires only that you remember that 180 degrees = π radians.
Use this relationship to set up a proportion (see Chapter 14) and convert the units.