Unlike the SAT, the ACT Math Test does not provide students with a formula chart to aid in solving problems—so unless you’ve got these memorized, you might find yourself up the creek without a paddle on the ACT. Print this list and learn it, students. Learn it well!
ACT Math Formula Chart
Circles
A = 
C = 
Rectangles, Parallelograms, and Squares
A = base x height
Triangles
A = bh/2
Trapezoids
A =
(Add the bases, divide by two, multiply by the height)
Rectangular Prisms
V = lwh
Cylinders
V = 
Spheres
V = 
Cones
Pyramids
V = 1/3 Bh
where B is the area of the base and h is the height
Pythagorean Theorem
(where c is the hypotenuse and a and b are legs of a right triangle)
Special Right Triangles
30° − 60° − 90° Right Triangle
Short leg (opposite the 30° angle) = x
Long leg (opposite the 60° angle) = x√3
Hypotenuse = 2x
45° − 45° − 90° Right Triangle
Each leg = x
Hypotenuse = x√2
Average (Arithmetic Mean)
Sum of things / number of things
Median
Middle number
Mode
Most frequent number
Trigonometry
SOHCAHTOA
sin x = opposite / hypotenuse
cos x = adjacent / hypotenuse
tan x = opposite / adjacent
In Quadrant I (top right), sin, cos, and tan are positive.
In Quadrant II (top left), sin is positive, and cos and tan are negative.
In Quadrant III (bottom left), sin and cos are negative, and tan is positive.
In Quadrant IV (bottom right), sin is negative, cos is positive, and tan is negative.
Probability
Number of desired outcomes / number of total outcomes
Factorials
5! = 5 x 4 x 3 x 2 x 1
Equation of a Circle
Logarithms
Change of Base Rule
Exponential Growth Formula
where A is the new amount, P is the principal amount, r is the rate of growth, n is the number of months, and t is time in years.
Quadratic Formula
Negative b plus or minus the square root of b squared minus 4ac over 2a.
