Critical DSAT Math Formulas You MUST Know

If you’re studying for the DSAT, you already know the Math section can feel like a big challenge. Between algebra, geometry, word problems, and tricky graphs, it’s easy to feel stuck when the right formula slips your mind. The good news? You don’t have to remember every formula from every math class you’ve ever taken. You just need the ones that the DSAT actually uses again and again.

This guide will give you a simple, no-nonsense list of the math formulas you really need, explained in plain language so you can actually remember and apply them on test day.

Why Formulas Matter More Than You Think

Here’s the thing: the DSAT doesn’t only test whether you can solve math problems. It also tests whether you can solve them quickly and without second-guessing yourself. Yes, the test booklet has a small formula sheet at the start, but it doesn’t include everything. And flipping back and forth wastes time.

Imagine you get a circle problem and blank out on circumference. Do you want to burn 30 seconds flipping to the front, or just jot down C = 2πr and move on? Every second counts, and those saved seconds often mean extra correct answers.

The Must-Know DSAT Math Formulas

Let’s go topic by topic so you can see exactly where to focus your memory.

1. Algebra & Lines

These show up constantly, so they’re non-negotiable.

Slope of a Line: m = (y₂ − y₁) / (x₂ − x₁) (Think “rise over run.” Simple and quick.)

Slope-Intercept Form: y = mx + b Where m is slope, and b is the y-intercept.

Point-Slope Form: y − y₁ = m(x − x₁)

👉 Why it matters: So many DSAT problems about graphs, speed, or cost are really just slope questions in disguise. If you’re fast with slope, you’ll save a lot of time.

2. Quadratic Equations

Quadratics always show up, and knowing more than one method helps.

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

Standard Form: ax² + bx + c = 0

Vertex Form: y = a(x − h)² + k Where (h, k) is the vertex.

💡 Quick tip: Don’t rely only on the quadratic formula. Sometimes factoring is faster, and the DSAT rewards speed.

3. Geometry Basics

Geometry isn’t the biggest part of the DSAT anymore, but a few formulas keep showing up.

Triangle Area: A = ½ × base × height Pythagorean Theorem: a² + b² = c²

Special Right Triangles:

• 45°-45°-90° → sides are x, x, x√2

• 30°-60°-90° → sides are x, x√3, 2x

Circles: A = πr², C = 2πr

Volume of a Rectangular Prism: V = l × w × h

👉 Why it matters: Word problems often sneak in triangles, circles, or 3D shapes. If these are memorized, you’ll fly through.

4. Statistics & Probability

Don’t skip these — they’re simple points if you know them.

• Mean (Average): Add all numbers, divide by how many there are.

Mean= Sum of values / Number of values

• Median: Middle value when ordered.

• Mode: Most frequent number.

• Range: Largest minus smallest.

Probability Formula: P(E) = Favorable outcomes / Total outcomes

Example: 3 red marbles, 7 blue marbles → probability of red = 3/10.

5. Exponents & Roots

These pop up more than you’d think.

• Product Rule: aᵐ × aⁿ = aᵐ⁺ⁿ

• Quotient Rule: aᵐ / aⁿ = aᵐ⁻ⁿ

• Power Rule: (aᵐ)ⁿ = aᵐⁿ

• Square Root Rule: √(a × b) = √a × √b
  

👉 Expect exponent problems in questions about growth, interest, or population.

6. Distance, Rate, and Time

A classic SAT word-problem formula:

Distance = Rate × Time

Example: Driving 60 mph for 2 hours = 120 miles.

Final Thoughts

DSAT Math doesn’t have to be scary. Once you know which formulas to focus on — and practice using them until they feel natural — you’ll notice the questions get easier and faster.

You don’t need every formula in the world. You just need the right ones, and the confidence to use them quickly. Learn these, practice often, and you’ll be way ahead on test day.