How High Is the Ceiling?
If your friend stood next to a wall in your living room and asked you how high the ceiling was, what
would you do? Would you get out your trigonometry textbook and try to triangulate using the shadow cast
by your pal? Of course not. You’d look at your friend and think something like this: “Dave’s about 6 feet
tall. The ceiling’s a couple of feet higher than he is. It must be about 8 feet high.”
Your Ballpark answer wouldn’t be exact, but it would be close. If someone later claimed that the ceiling
in the living room was 15 feet high, you’d be able to tell her with confidence that she was mistaken.
You’ll be able to do the same thing on the SAT. Every geometry figure on your test will be drawn exactly
to scale unless there is a note in that problem telling you otherwise. That means you can trust the
proportions in the drawing. If line segment A has a length of 2 and line segment B is exactly half as long,
then the length of line segment B is 1. All such problems are ideal for Ballparking.
The Correct Choice
Remember that the SAT
is a multiple-choice
test. This means that
you don’t always have to
come up with an answer;
you just have to
identify the correct one
from among the four
choices provided.