32 Math Formulas on the ACT - What to Absolutely Study [PDF]

9 Unlike the SAT, the ACT does not provide you with a list of basic math formulas to rely upon at the beginning of the ACT math test. This means you will need to be able to recall math formulas on the ACT. Below you will find lists of â€Å"Must Know† ACT math formulas, â€Å"Good to Know† formulas, and â€Å"Bonus† formulas to commit to memory for the ACT! Learn them all, then check out our list of ACT math topics to begin applying them! Must-Know ACT Math Formulas Though the ACT tests different concepts on each exam, there are popular topics that come up again and again. This list contains the best ACT math formulas to know. For more practice, try Magoosh ACT prep. Average S/T (Average = Sum/Number of things) Lines Slope intercept form: y = mx + b (where m is the slope and b is the y-intercept) Slope Triangles Area of a triangle: 1/2bh (1/2 base x height) Pythagorean Theorem Quadrilaterals Perimeter of a rectangle: 2l + 2w (where l is the length and w is the width) Area of a rectangle: lw (length x width) Volume of a box: lwh (length x width x height) Surface area of a rectangular solid: 2lw + 2wh + 2lh Diagonal in a rectangular solid Apply the Pythagorean theorem twice or Circles and Spheres Area of a circle: Circumference of a circle: Volume of a sphere: Cylinders Volume of a cylinder: Trigonometry SOHCAHTOA: sin x = opposite/hypotenuse cos x = adjacent/hypotenuse tan x = opposite/adjacent You should also know your quadrants and where sine, cosine, and tangent are positive or negative: Probability Probability: Number of desired outcomes / number of total outcomes Factorials (e.g. 8!): To find the factorial of any integer, multiply it by every positive integer below it, e.g.: 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 Bonus: the Must Know math formulas on the ACT also appear in your high school math classes. So, youre really studying for two things at once. Nice. Bonus bonus: Check out the video below to watch ACT expert Kristin discuss 6 of the must-know ACT math formulas in greater detail: ACT Formulas that are Good to Know Volume and Area Volume of a cone: Volume of a pyramid: Area of a trapezoid: (Add the bases, divide by two, then multiply by the height.) Logarithms Definition: Change of base rule: Triangles 30-60-90 Triangle Ratio: 45-45-90 Triangle Ratio: Additional Formulas Equation of a circle: Arithmetic sequences: Geometric sequences: Exponential Growth Formula: Where P = principal (starting value), r = rate of growth, n = number of months, t = time in years, and A = new amount. Bonus Things to Know Quadratic Equation: Often, you will be better off applying a strategy such as backsolving to solve a complicated algebra problem, but if you are comfortable with the quadratic equation, keep it in the back of your mind. Permutations: Combinations: An Important Note About ACT Math Formulas Occasionally, an ACT math problem may rely upon a more advanced formula, such as the surface area of a sphere. In these cases, the question itself will typically provide you with the formula you need. So no need to think you need to memorize everything. However, being able to recall basic formulas will ensure you can tackle problems that dont provide a formula with confidence! The list below includes formulas for the concepts the ACT tests most frequently. Important ACT Math Formulas to Know (PDF) Sometimes its easier to memorize formulas by studying a little bit every day. To make this easier, we created a printable Magoosh ACT Math Formulas PDF. Heres the link where you can get your copy. Let us know if you have any questions about these ACT formulas. 🙂 Image Credit: hotmath.com and getmathhelp.jimdo.com