GED & HiSET Math Formula Cheat Sheet (Essential Formulas)
If you’re preparing for a high school equivalency math test like the GED or HiSET, knowing the key formulas can make a real difference, even though these tests provide a formula sheet. Understanding the essential GED math formulas (which are the same ones the HiSET and other equivalency tests use) means you can apply them quickly and confidently rather than hunting through the reference sheet under time pressure. This cheat sheet collects the formulas you most need to know, explains what each does, and shows how to use them, so you walk in ready.
Whether your state uses the GED, the HiSET, or another high school equivalency test, the math, and these formulas, are essentially the same. Below we’ll cover the formulas for geometry, algebra, and data, paired with steady HSE math practice that turns memorized formulas into usable skills for a passing GED math or HiSET score.
Why know the formulas if a sheet is provided?
Both the GED and HiSET give you a formula reference sheet during the math test, so why memorize formulas? Because knowing them saves time and reduces errors. A test-taker who knows the formulas applies them instantly, while one who must look up each formula loses valuable time and risks misreading the sheet under pressure.
Just as importantly, the formula sheet only helps if you know which formula a problem calls for and how to use it. Familiarity with the formulas, knowing what each represents and when to apply it, is what makes the reference sheet useful rather than confusing. This cheat sheet builds that familiarity.
Area formulas
Area measures the space inside a two-dimensional shape, and several area formulas appear regularly. The area of a rectangle is length times width. The area of a triangle is one-half times base times height. The area of a square is side squared, and the area of a parallelogram is base times height.
These show up in both pure geometry questions and applied word problems about floors, walls, gardens, and more. Knowing them cold lets you focus on setting up the problem rather than recalling the formula. They’re a small, finite set, easy to learn with a little practice.
The area of a circle
Circles have their own key formulas. The area of a circle is pi times the radius squared, and the circumference (the distance around) is two times pi times the radius, or pi times the diameter. Remember that the radius is half the diameter, a common point of confusion.
Circle problems appear in geometry and applied contexts, so knowing these formulas and the radius-diameter relationship is valuable. Pi is approximately 3.14, and the formula sheet provides it, but knowing how to apply the circle formulas quickly is what earns the points efficiently.
Perimeter formulas
Perimeter is the distance around a two-dimensional shape. For a rectangle, the perimeter is twice the sum of length and width. For a square, it’s four times the side length. For other polygons, you simply add up the lengths of all the sides.
Perimeter questions are common, especially in applied problems about fencing, framing, or borders. These formulas are straightforward, but knowing them automatically prevents the small slips that cost points. Distinguishing perimeter (around) from area (inside) is also worth keeping clear.
Volume formulas
Volume measures the space inside a three-dimensional figure. The volume of a rectangular prism (box) is length times width times height. The volume of a cylinder is pi times the radius squared times the height. The volume of a cube is side cubed.
Volume formulas appear in applied problems about containers, tanks, and packaging. Knowing them, and recognizing which figure a problem describes, lets you handle these questions confidently. As with area, the formula sheet lists them, but fluency with applying them is what saves time on the test.
The Pythagorean theorem
One of the most useful formulas in all of math, the Pythagorean theorem states that in a right triangle, a squared plus b squared equals c squared, where c is the hypotenuse (the longest side, opposite the right angle). This lets you find a missing side of a right triangle.
The Pythagorean theorem appears in geometry and coordinate-plane problems and is worth knowing thoroughly. Remember that it applies only to right triangles, and that c is always the hypotenuse. Practicing problems that use it ensures you recognize when and how to apply this powerful, frequently tested formula.
Slope and linear equations
For algebra and coordinate geometry, the slope formula is essential: the slope between two points is the difference in their y-values divided by the difference in their x-values (rise over run). The slope-intercept form of a line, y equals mx plus b, where m is slope and b is the y-intercept, is equally important.
These appear in the many GED and HiSET questions about lines and linear relationships. Knowing how to find slope and write or interpret a line’s equation lets you handle this common content efficiently. Linear relationships are a major topic, so these formulas are among the most valuable to know cold.
The quadratic formula
For quadratic equations in the form ax squared plus bx plus c equals zero, the quadratic formula gives the solutions: x equals negative b, plus or minus the square root of b squared minus four a c, all divided by two a. This solves any quadratic, even those that don’t factor easily.
While quadratics are a smaller part of equivalency tests than linear equations, knowing the quadratic formula prepares you for the questions that do appear. Memorizing it precisely, including the plus-or-minus and the order under the square root, prevents the errors that cost points on these problems.
Mean, median, mode, and range
For data and statistics questions, know these measures: the mean is the average (sum of values divided by the number of values); the median is the middle value when data is ordered; the mode is the most frequent value; and the range is the difference between the largest and smallest values.
These appear in the data-analysis portion of equivalency tests, which is a meaningful share of the math. Knowing how to calculate each, and what each represents, lets you handle data questions quickly. They’re simple but commonly tested, so they’re well worth having at your fingertips.
Percentages, ratios, and proportions
Many word problems involve percentages and proportions. Remember that a percentage is a part over a whole times one hundred, and to find a percent of a number, multiply by its decimal form. For proportions, set two ratios equal and cross-multiply to solve for the unknown.
These relationships drive a large share of applied problems, from discounts to rates to scaling. Being fluent with converting among fractions, decimals, and percentages, and with setting up proportions, is essential. These aren’t flashy formulas, but they’re among the most frequently used skills on any equivalency math test.
Practice applying the formulas
Memorizing formulas is only half the job; using them in practice is what makes them stick and useful. Math Notion offers free, printable GED math worksheets that let you apply these formulas to real test-style problems, so they become automatic skills rather than abstract rules.
Browse the full library on our math worksheets page for more practice. Work problems that require each formula, check your solutions, and review any mistakes. This applied practice transforms a memorized list into the confident, automatic recall that equivalency tests reward.
The workbook that brings it together
For complete, structured preparation, a workbook ties the formulas, concepts, and practice together. Math Notion’s high school equivalency math resources cover exactly the geometry, algebra, and data the GED and HiSET test, with clear lessons that explain each formula and step-by-step answer explanations that show how to apply them.
Paired with the free worksheets for applied practice, a workbook gives you both complete instruction and focused drilling on the formulas this cheat sheet covers. It’s an instant download, so you can start tonight and build toward a passing score. Browse all our HSE math resources → to find the right fit.
How to memorize the formulas effectively
The best way to learn these formulas isn’t flashcards alone but using them in practice. As you work problems, you’ll naturally reinforce the formulas you need most, and writing each one out as you apply it, while saying what each part means, cements both the formula and its purpose. Understanding why the area of a triangle is half base times height, or why c is the hypotenuse in the Pythagorean theorem, makes the formula far easier to recall correctly under pressure.
Group the formulas by category, geometry, algebra, data, so they’re organized in your mind, and focus extra attention on the ones tied to the most common question types, especially area, the Pythagorean theorem, slope, and the statistics measures. A little review each day, combined with applied practice, builds reliable recall far better than cramming the whole list at once, and it ensures the formulas are there when you need them on test day.
A note on discontinued equivalency tests
If you arrived here looking for the TASC, note that the TASC has been discontinued; states that used it have moved to the GED, the HiSET, or another high school equivalency option. The good news is that the math, and these formulas, carried over almost entirely, so nothing you study is wasted. Whatever equivalency test your state now uses, the geometry, algebra, and data formulas in this cheat sheet are exactly the ones you’ll need.
So focus your preparation on the current test your state offers, the GED or HiSET in most cases, and use these formulas, the free worksheets, and a workbook to get ready. The credential you’ll earn is the same, and the math you build now serves you well beyond the test, in college placement, training programs, and everyday life. Knowing these formulas cold is a small, high-value step toward that goal.
Frequently asked questions
Do I need to memorize formulas if a sheet is provided?
The GED and HiSET provide a formula sheet, but knowing the formulas saves time and reduces errors, and the sheet only helps if you know which formula to use and how to apply it.
What are the most important formulas to know?
Area, perimeter, and volume formulas; the area and circumference of a circle; the Pythagorean theorem; slope and slope-intercept form; the quadratic formula; mean, median, mode, and range; and percentage and proportion relationships.
Are GED and HiSET math formulas the same?
Essentially yes. Both tests measure the same high school equivalency math, so the key formulas, and the practice that builds them, apply to either test.
How do I learn the formulas?
Through applied practice and understanding. Use the formulas in real problems, learn what each part means, and practice until recall is automatic. Free worksheets and a workbook both help.
Math Notion makes standards-aligned math workbooks and test prep for learners at every level and across all 50 states. See the full collection.
