Slope-intercept form: y = mx + b, where m is slope and b is the y-intercept.

Slope between two points: m = (y₂ − y₁) / (x₂ − x₁)

Point-slope form: y − y₁ = m(x − x₁)

Standard form: ax² + bx + c = 0

Quadratic formula: x = (−b ± √(b² − 4ac)) / 2a

Factored form: a(x − r₁)(x − r₂), where r₁ and r₂ are roots.

Discriminant: b² − 4ac. Positive = two real roots, zero = one, negative = no real roots.

xᵃ · xᵇ = x^(a+b)

xᵃ / xᵇ = x^(a−b)

(xᵃ)ᵇ = x^(ab)

x⁻ᵃ = 1 / xᵃ

x⁰ = 1

Percent change = (new − old) / old × 100

Part = percent × whole

Example: 30% of 150 = 0.30 × 150 = 45.

Area: A = πr²

Circumference: C = 2πr or C = πd

Equation (center at origin): x² + y² = r²

Pythagorean theorem: a² + b² = c² (right triangles only)

Area: A = ½ × base × height

Triangle angle sum: 180°

45-45-90: legs = x, hypotenuse = x√2

30-60-90: short leg = x, long leg = x√3, hypotenuse = 2x

Rectangle: A = length × width

Triangle: A = ½ × base × height

Circle: A = πr²

Rectangular prism volume: V = length × width × height

Cylinder volume: V = πr²h

sin(θ) = opposite / hypotenuse

cos(θ) = adjacent / hypotenuse

tan(θ) = opposite / adjacent

Mean (average): sum of values ÷ number of values

Median: the middle value when the data is sorted

The digital SAT provides a reference sheet with some geometry formulas and unit conversions, and a built-in Desmos graphing calculator is available for the entire Math section. Still, memorizing the formulas above will save you time on test day.