Up Your Score SAT, 2018-2019 Edition The Underground Guide to Outsmarting The Test

For those of you who prefer to memorize formulas, here is the monstrous
(and easily forgettable) distance formula, from one point (x 1 , y 1 ) to another point
(x 2 , y 2 ):*

*It doesn’t matter  which   point   you call    “point  1”  and which   one you call    “point  2.” You will    get the same    answer  either  way.

—Samantha

The midpoint, on the other hand, is easier to calculate using a formula,
because the formula is much easier to remember. It’s just the average of the x
values and the average of the y values:

What    is  the midpoint    between the points  (–2,2)  and (10,4)?

x-coordinate:   

y-coordinate:   

The midpoint    is  (4,3).

A FEW MORE SYMBOLS

It’s possible you will see these on the SAT, so you should know what they are:

a   line    with    A   and B   as  points  on  the line

a   ray with    point   A   as  an  endpoint

a   line    segment with    A   and B   as  endpoints

ΔABC    ≅   ΔDEF triangle   ABC is  congruent   (equal) to  triangle    DEF

ΔABC    ~   ΔDEF triangle   ABC is  similar to  triangle    DEF

CIRCLES
A circle looks pretty familiar, even when plotted on a graph: