# SAT Math Formula Sheet: What You Must Know

The math portion of the SAT is designed to make you apply math concepts you’ve used before in new ways. To get a high score on the test, you’ll need to know some basic math formulas.

You will be given some formulas, but to save time during SAT testing, it can be helpful to get to know the formulas below:

**Circles**

For circles, it will be helpful for you to know how to find the length of an arc. The formula is:

Larc=(2πr)(degree measure center of arc/360)

Next, familiarize yourself with the formula for finding the area of an arc sector:

Aarcsector=(πr2)(degree measure center of arc/360)

Formulas for the area of a circle and circumference are generally given on the test, as well.

**Slopes and Graphs**

It’s vital to know the slope formula that is used to find the slope of a line. Remember “rise over run” – that is, the vertical change will be divided by the horizontal change of the line.

You’ll also want to know how to write the equation of a line:

y=mx+b

If there is an equation that is not in this form, remember to re-write it so that it is! On the SAT, it’s common for an equation to be given in a specific form, then to ask whether the intercept and slope are negative or positive so that students are required to flip around the terms of the original formula.

If you don’t re-write the equation into the form y=mx+b, you will get those questions wrong.

If you are given two points — A(x1,y1), B(x2,y2) — you must find the midpoint of the line that connects them. This is known as the midpoint formula, which is written as:

Given two points, A(x1,y1), B(x2,y2), you may be asked to find the distance between them. The distance formula is written as:

**Algebra Formulas**

There are a few crucial algebra formulas you will want to know for the SAT, as well.

The quadratic equation asks you to solve for x when given ax2+bx+c. It is written as:

Some of the polynomials you will see on the SAT are easier to factor than others. For the ones that are difficult to factor, the quadratic equation will prove to be invaluable.

**Percentages**

For the SAT, you’ll need to know how to find x percent of a given number (n). Use the following formula:

To find what percent a certain number, n, is of another number, m, the formula is:

Finally, make sure you know how to find out what number (n) is a certain percent of (x) with this formula:

**Averages**

For the SAT, you will need to remember that the mean is the same thing as the average. With this in mind, if you are asked to find the mean or average of a set of numbers, use this formula:

If you are asked to find the average speed of something, use the following formula:

**Probabilities**

When you come across problems in which you need to work with probabilities, keep in mind that probabilities represent the odds of something specific happening. The formula is:

Keep in mind that a probability of 0 will never happen, while a probability of 1 will be guaranteed to happen.

**SAT Prep with Jantzi**

There is so much more to doing well on the SAT than just knowing the right math formulas. Earning a high SAT score is vital to getting into the college of your choice. Contact the team at Jantzi today for more information on our test prep services so that you can be fully prepared.