The Math reference sheet provided on every Digital SAT question: circle and triangle area, the Pythagorean theorem, the special right triangles, common volumes, and the angle and radian facts.

What this topic is asking

Bluebook shows a reference sheet on every Digital SAT Math question, so you do not have to memorize the common geometry formulas. But the sheet only helps if you can find the right formula in seconds and apply it cleanly. This topic is a tour of what the sheet contains and how to use each part at speed.

What the sheet provides

The sheet is a fixed set of measurement formulas and facts.

Using the special right triangles

The special-triangle ratios are the highest-value entries because they replace a slow calculation with one multiplication.

What the sheet does not give you

The sheet covers geometry measurement formulas and angle facts, and nothing else. It does not give you the quadratic formula, slope, the laws of exponents, percentage formulas, statistics formulas, or trigonometric ratio definitions. Those you must know. In particular, right-triangle trigonometry (SOH-CAH-TOA: $\sin = \frac{\text{opp}}{\text{hyp}}$, $\cos = \frac{\text{adj}}{\text{hyp}}$, $\tan = \frac{\text{opp}}{\text{adj}}$) is tested but not on the sheet, so memorize the three ratios even though the special-triangle side ratios are provided.

Building the habit

The sheet is most useful when you barely have to think about it. During practice, get into the habit of opening it for any area, volume, Pythagorean, or special-triangle step, so that on test day the motion is automatic and you trust the formula rather than a half-remembered version. Equally, learn what is not on it so you are never caught hunting for the quadratic formula or a trig ratio that is yours to supply. The reference sheet removes memory risk from geometry; your job is to remove the rest by knowing the algebra, statistics and trig formulas cold.

A second habit worth building is combining a sheet formula with the calculator. The two provided tools work together: read the right formula off the sheet, then let Desmos do the arithmetic. For a cylinder of radius $3$ and height $10$, the sheet gives $V = \pi r^2 h$; typing $\pi \cdot 3^2 \cdot 10$ into Desmos returns about $282.7$ in one step. For a circle problem, pull $A = \pi r^2$ from the sheet and evaluate it in Desmos rather than by hand. This division of labour, the sheet for which formula and Desmos for the number, is faster and far less error-prone than reconstructing a formula from memory and computing it by hand. Treat the reference sheet and the calculator as a pair, and most geometry questions become a two-step routine: find the formula, then compute.