The digital SAT's on-screen reference sheet feels reassuring, but it only covers part of what you'll actually need. This guide lays out what's genuinely printed on the sheet, what commonly-needed formulas are missing, works through two full examples using formulas you have to bring yourself, and gives you a checklist to test your own memory before test day.
What's actually printed on the reference sheet
The digital SAT reference sheet includes a defined, limited set of formulas: the area and circumference of a circle, the volume of a handful of common solids, the fact that a triangle's interior angles sum to \(180^\circ\), and the side ratios for the two special right triangles (30-60-90 and 45-45-90). That's genuinely useful, but it's a shorter list than most students expect — and treating it as a complete formula reference is a common and costly assumption. Nothing about angle relationships in parallel lines, nothing about trapezoids or parallelograms, and nothing about trigonometry beyond those two triangle shapes appears anywhere on the sheet.
Coordinate geometry formulas you have to know yourself
None of the core coordinate geometry formulas appear on the reference sheet, which means these need to live in memory, not on screen:
- Distance between two points: \(d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\)
- Midpoint of a segment: \(\left(\frac{x_1+x_2}{2}, \frac{y_1+y_2}{2}\right)\)
- Slope between two points: \(m = \frac{y_2-y_1}{x_2-x_1}\)
Our full breakdown of coordinate geometry on the SAT covers how these formulas get tested in practice, including how the distance formula quietly reappears inside every circle equation question.
Trig ratios, arc formulas, and other common gaps
A few other formulas that students often assume are covered, but aren't, include:
- The trig ratio definitions themselves — SOH-CAH-TOA isn't spelled out anywhere on the sheet, even though the special right triangle ratios are.
- Arc length and sector area formulas, which you have to build yourself from the idea of a fraction of the full circle. Our guide to circles on the SAT walks through both formulas in detail.
- Area formulas for shapes beyond the circle — trapezoids and parallelograms in particular are easy to forget precisely because the sheet trains you to expect area formulas to be provided.
- Angle relationship rules for parallel lines and transversals, and the exterior angle theorem for triangles — none of which appear despite the triangle-angle-sum fact being included.
Worked example: using the distance formula from memory
Find the distance between the points \((1, 2)\) and \((4, 6)\).
- Write the distance formula: \(d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2}\).
- Substitute the coordinates: \(d = \sqrt{(4-1)^2 + (6-2)^2}\).
- Simplify inside the square root: \(d = \sqrt{3^2 + 4^2} = \sqrt{9+16} = \sqrt{25}\).
- \(d = 5\).
Notice the 3-4-5 pattern hiding inside the numbers — the distance formula is just the Pythagorean theorem in disguise, which is a useful mental shortcut if you ever blank on the formula itself.
Worked example: sector area from memory
A circle has a radius of 6 units and a central angle of \(90^\circ\). Find the area of the sector, without any formula printed on the reference sheet to guide you.
- Start from the idea a sector represents: a fraction of the full circle's area, based on how much of the full \(360^\circ\) the central angle covers.
- The central angle is \(90^\circ\), so the sector covers \(\frac{90}{360} = \frac{1}{4}\) of the circle.
- The full circle's area is \(\pi r^2 = \pi (6)^2 = 36\pi\).
- Multiply by the fraction: \(\frac{1}{4} \times 36\pi = 9\pi\) square units.
Notice that nothing here required a memorized "sector area formula" — just the reference sheet's own circle area formula, combined with the reasoning that a sector is a fraction of the whole. That's the pattern for handling every "not given" formula on this test: build it from something you do have, rather than treating the gap as a dead end.
A quick memorization checklist
Before test day, make sure you can write each of the following without looking anything up:
| Formula | On reference sheet? |
|---|---|
| Circle area and circumference | Yes |
| Volume of common solids | Yes (a subset) |
| Triangle angle sum | Yes |
| Special right triangle ratios | Yes |
| Distance, midpoint, slope formulas | No |
| SOH-CAH-TOA trig ratios | No |
| Arc length and sector area | No |
| Trapezoid and parallelogram area | No |
| Parallel line angle relationships | No |
Quick tip: don't just memorize this list once — test yourself by writing every formula from memory a few days before you practice, then check what you missed. That gap is exactly where your review time should go.
Frequently asked questions
Should I even bother checking the reference sheet during the test?
Yes — it's still useful for the formulas it does include, especially the special right triangle ratios, which are easy to mix up under time pressure. Just don't assume it covers everything.
What's the single most commonly forgotten "not given" formula?
The distance formula and the general trig ratio definitions are the two most frequently underestimated, largely because students conflate them with the special right triangle ratios that actually are provided.
Is there a general strategy for handling a formula that isn't on the sheet?
Yes — look for a way to build it from something that is provided. Sector area builds from circle area, the distance formula builds from the Pythagorean theorem, and trapezoid area builds from the idea of an averaged rectangle. Very few "missing" formulas are truly disconnected from something the reference sheet does give you.
How do I build these formulas into memory efficiently?
Practicing against real questions works better than flashcards alone. Our instant-scored SAT Math sets flag exactly which formula a missed question depended on, so your review time goes to the right gaps.