Cheat Sheet with ACT Math Formulas
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Cheat Sheet -ACT math Formulas for Coordinate Geometry
Midpoint x: (x1 + x2) ÷ 2
Midpoint y: (y1 + y2) ÷ 2
x and y intercepts:
These are the points where the line on a two-dimensional graph intersects with the x and y axes.
You will see an algebraic equation which represents the line on the two-dimensional graph.
The equation will contain the variables x and y.
To calculate the x intercept, substitute 0 for y.
To calculate the y intercept, substitute 0 for x.
y = mx + b
m = slope
b = y intercept
x, y = points on the graph or in the equation
Cheat Sheet-ACT math Formulas for Plane Geometry
Area of circle:
π × R2 (radius squared)
Area of square or rectangle:
length × width
Area of triangle:
(base × height) ÷ 2
Arc length is the distance on the outside of a circle.
Calculate the circumference for the part of circle for the degrees stated.
A chord is a straight line which is drawn inside a circle.
That line connects two points on the circumference of the circle.
Use the degrees stated for the given angle to calculate chord length.
Circumference of a circle:
π × diameter
diameter = radius × 2
(π × radius2 × height) ÷ 3
V = πr2h
Volume = π times the radius squared times the height
Length of hypotenuse = square root of the sum of the squares of the other two sides
Perimeter of squares and rectangles:
(length × 2) + (width × 2)
Cheat Sheet-ACT math Formulas for Trigonometry
θ = s ÷ r
θ = radians
s = arc length
r = radius
π × 2 × radians = 360°
π × radians = 180°
π ÷ 2 × radians = 90°
π ÷ 4 × radians = 45°
π ÷ 6 × radians = 30°
Tangent, sine, and cosine:
cos2 A + sin2 A = 1
cos2 A = 1 − sin2 A
sin2 A = 1 − cos2 A
tan A = sin A ÷ cos A