About this Flash Card Set
14 Cards
by hannah_cole
Essential math formulas and concepts for the SAT and ACT: geometry, algebra, and coordinate geometry. Memorize these to save time on test day.
Front
Slope formula
Back
m = (y₂ − y₁) / (x₂ − x₁) — the steepness of a line between two points.
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Front
Slope-intercept form
Back
y = mx + b, where m is the slope and b is the y-intercept.
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Front
Distance formula
Back
d = √[(x₂ − x₁)² + (y₂ − y₁)²] — distance between two points.
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Front
Midpoint formula
Back
((x₁ + x₂)/2, (y₁ + y₂)/2) — the point halfway between two points.
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Front
Pythagorean theorem
Back
a² + b² = c², where c is the hypotenuse of a right triangle.
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Front
Area of a triangle
Back
A = ½ × base × height.
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Front
Area & circumference of a circle
Back
Area = πr²; Circumference = 2πr.
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Front
Quadratic formula
Back
x = [−b ± √(b² − 4ac)] / 2a — solves ax² + bx + c = 0.
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Front
Sum of angles in a triangle
Back
Always 180°.
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Front
Special right triangles
Back
30-60-90: sides x, x√3, 2x. 45-45-90: sides x, x, x√2.
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Front
Percent change
Back
(new − old) / old × 100%.
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Front
Average (mean)
Back
Sum of values ÷ number of values.
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Front
Exponent rules
Back
xᵃ · xᵇ = xᵃ⁺ᵇ; (xᵃ)ᵇ = xᵃᵇ; x⁰ = 1.
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Front
SOHCAHTOA
Back
sin = opp/hyp, cos = adj/hyp, tan = opp/adj — right-triangle trigonometry.
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