SAT & ACT Math Formula Cheat Sheet & Strategy Guide

Q: Which formulas are provided on the SAT math reference sheet?

The digital SAT provides geometry formulas including area of circles, triangles, rectangles, volume of prisms, cones, spheres, and special right triangle ratios. However, critical algebra and coordinate formulas like slope, quadratic formula, and circle equations are NOT provided and must be memorized.

Q: Are calculators allowed on all SAT Math questions?

Yes! On the digital SAT (DSAT), graphing calculators are permitted on the ENTIRE math section. An embedded Desmos graphing calculator is also accessible on every math question.

Q: What is the best pacing strategy for SAT & ACT math?

Target spending 45 to 60 seconds on easy and medium questions. This preserves 1.5 to 2 minutes for hard multi-step problems and data interpretation questions at the end of each module.

Table of Contents

2. Essential Quadratic & Polynomial Rules
3. Geometry, Circles & Trigonometry Formulas
4. Statistics, Probability & Data Interpretation
5. Step-by-Step Worked Exam Questions
6. Time Management & Plug-In Strategies

Scoring 700+ on SAT Math or 30+ on ACT Math isn't about memorizing entire textbooks—it's about mastering 15 core high-yield formulas and recognizing patterns instantly under pressure. In this ultimate guide, we break down essential exam formulas, step-by-step worked practice questions, and time-saving shortcuts.

Algebra represents over 35% of all questions on the Digital SAT and ACT. Mastery over slope, linear functions, and systems of equations guarantees easy points.

Formula 1: Slope & Linear Equations

• Slope (m): m = (y₂ - y₁) / (x₂ - x₁) • Slope-Intercept Form: y = mx + b (m = slope, b = y-intercept) • Point-Slope Form: y - y₁ = m(x - x₁)

Exam Tip: Parallel lines have identical slopes (m₁ = m₂). Perpendicular lines have negative reciprocal slopes (m₁ · m₂ = -1). For example, if a line has a slope of 3/4, any perpendicular line has a slope of -4/3.

Formula 2: Midpoint & Distance

• Midpoint Formula: M = ( (x₁ + x₂)/2 , (y₁ + y₂)/2 ) • Distance Formula: d = √[ (x₂ - x₁)² + (y₂ - y₁)² ]

You can quickly verify linear equations and distances using our free Interactive Linear Equation Solver.

2. Essential Quadratic & Polynomial Rules

Quadratic equations appear heavily across both exam modules. Memorizing the quadratic equation and vertex conversions eliminates algebraic paralysis.

Formula 3: The Quadratic Formula & Discriminant

• Quadratic Formula: x = [ -b ± √(b² - 4ac) ] / (2a) • Discriminant (Δ): Δ = b² - 4ac

If Δ > 0: 2 real, distinct solutions.
If Δ = 0: 1 real solution (double root).
If Δ < 0: 0 real solutions (2 complex conjugate roots).

Formula 4: Vertex Form & Vieta's Formulas

• Vertex Form: y = a(x - h)² + k (Vertex is at (h, k)) • Axis of Symmetry: x = -b / (2a) • Sum of Roots: -b / a • Product of Roots: c / a

Need to solve a complex quadratic equation step-by-step? Try our Quadratic Formula Solver with Step-by-Step Solutions.

3. Geometry, Circles & Trigonometry Formulas

While the SAT provides a basic reference sheet for geometry, ACT does not. Furthermore, circle equations and trigonometric identities are expected knowledge on both exams.

Formula 5: Standard Equation of a Circle

• Circle Equation: (x - h)² + (y - k)² = r² • Center: (h, k) | Radius: r

Formula 6: Trigonometric Ratios & Fundamental Identity

• SOH CAH TOA: sin(θ) = Opp/Hyp | cos(θ) = Adj/Hyp | tan(θ) = Opp/Adj • Pythagorean Identity: sin²(θ) + cos²(θ) = 1 • Complementary Angle Rule: sin(x°) = cos(90° - x°)

Explore angle calculations and right triangle geometry using our Scientific Calculator & Trig Tool.

4. Statistics, Probability & Data Interpretation

Formula 7: Mean, Median, and Weighted Averages

• Mean (Average): Mean = (Sum of all values) / (Total count) • Combined Average: (Sum₁ + Sum₂) / (Count₁ + Count₂)

Formula 8: Probability & Combinatorics

• Probability: P(E) = (Favorable Outcomes) / (Total Outcomes) • Combinations: nCr = n! / [ r! (n - r)! ] • Permutations: nPr = n! / (n - r)!

5. Step-by-Step Worked Exam Questions

Practice Question 1: Quadratic Discriminant

Question: For what value of k does the equation 3x² - 6x + k = 0 have exactly one real solution?

Solution:

For exactly one real solution, the discriminant must equal zero: b² - 4ac = 0.
Identify parameters: a = 3, b = -6, c = k.
Substitute into discriminant: (-6)² - 4(3)(k) = 0 ⟹ 36 - 12k = 0.
Solve for k: 12k = 36 ⟹ k = 3.

Answer: k = 3.

Practice Question 2: Circle Geometry

Question: A circle in the xy-plane has equation x² + y² - 8x + 6y = 0. What is the radius of the circle?

Solution:

Group x and y terms: (x² - 8x) + (y² + 6y) = 0.
Complete the square for x: Add (8/2)² = 16.
Complete the square for y: Add (6/2)² = 9.
Balance equation by adding 16 + 9 = 25 to the right side: (x - 4)² + (y + 3)² = 25.
Since r² = 25, radius r = √25 = 5.

Answer: Radius is 5 units.

6. Time Management & Plug-In Strategies

The 45-Second Rule: Solve easy arithmetic/algebra problems in 45 seconds or less to bank time for 2-minute complex word problems.
Back-Solving (Plug-In Choices): When an algebra problem contains numeric options (A, B, C, D), test Choice B or C first to determine whether to go higher or lower.
Pick Numbers for Variables: Replace abstract variables like n or x with simple prime numbers like x = 2 or x = 3 to simplify complex algebraic expressions quickly.

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7. Frequently Asked Questions (FAQs)

Which formulas are provided on the SAT math reference sheet?

The digital SAT provides geometry formulas including area of circles, triangles, rectangles, volume of prisms, cones, spheres, and 30-60-90 / 45-45-90 right triangle ratios. Critical algebra, slope, quadratic formula, and circle equations are NOT provided.

Are graphing calculators allowed on all SAT Math questions?

Yes! On the Digital SAT (DSAT), graphing calculators are permitted on the entire math section. An embedded Desmos graphing calculator is also accessible directly inside the exam app interface.

What is the best pacing strategy for SAT & ACT math?

Target spending 45 to 60 seconds on easy and medium questions. This preserves 1.5 to 2 minutes for hard multi-step problems and data interpretation questions at the end of each module.