The 3 most important GMAT math formulas

GMAT math
By Leila

To solve many of the quantitative questions on the GMAT, it is essential to understand a couple key equations. This article will clearly lay out 3 very important formulas.  

1. Pythagorean Theorem: a2 + b2 + = c2

The Pythagorean Theorem only applies to right triangles, which is a triangle that has one angle measured 90 degrees. In this equation, a and b represent the two legs of the triangle (shorter sides) and c represents the hypotenuse (longer side opposite the right angle). This theorem helps solve many different GMAT Quantitative geometry questions. For example, you might be given that it is a right triangle and the lengths of two of the sides, and you will be then asked to find the length of the 3rd side by plugging into the above equation.

Be sure to also review common Pythagorean triples such as 3: 4: 5 and 5: 12: 13 and 6: 8: 10, in addition to 45-45-90 and 30-60-90 triangles.

2. Average, Sums, and Weighted Average

Screen Shot 2022-04-19 at 5.31.56 PMThe average is the sum of all the numbers in a list divided by the number of items in the list. This average formula can be rearranged to isolate the “sum” of the items. By multiplying both sides by “number of items,” you would then have the formula, sum of items = average * number of items. The GMAT expects students to leverage this formula for many different problems.

Screen Shot 2022-04-19 at 5.32.45 PMThe weighted average is similar to typical average questions; however, the difference is that not all values in the set contribute uniformly to the mean. For the purposes of the GMAT, this topic could come up in a problem where we are asked to combine groups with different sizes and group averages. In problems such as this, the goal would be to find the average of all groups together. Keep in mind that although this is the primary equation to solve the weighted average, you can also solve weighted average problems through leveraging 1) proportions / percentages of each group and 2) proportional placement of total averages.

3. Distance equation: Distance = speed * time

Distance refers to how far apart things are (e.g., points, people, places), speed refers to the rate of travel, and time refers to how long it takes to travel. Distance problems are very common on the GMAT, and they make up a majority of the quantitative section (almost 60%!). Beyond this simple distance equation, another important topic is average speed.

Screen Shot 2022-04-19 at 5.34.23 PMAverage speed, as seen above, is the total distance traveled over the total time spent traveling. Even if you have multiple parts of one trip, you will have to add up the distances of each part and then divide it by the total time of each part. In a sense, average speed captures the constant speed needed to travel the total distance in the total time.

Comments

topicTopics
academics study skills MCAT medical school admissions SAT expository writing college admissions English MD/PhD admissions strategy writing LSAT GMAT GRE physics chemistry math biology graduate admissions ACT academic advice interview prep law school admissions test anxiety language learning premed MBA admissions career advice personal statements homework help AP exams creative writing MD study schedules test prep Common Application computer science summer activities history philosophy mathematics organic chemistry secondary applications economics supplements research 1L PSAT admissions coaching grammar law psychology statistics & probability legal studies ESL CARS SSAT covid-19 dental admissions logic games reading comprehension engineering USMLE calculus PhD admissions Spanish mentorship parents Latin biochemistry case coaching verbal reasoning DAT English literature STEM excel medical school political science AMCAS French Linguistics MBA coursework Tutoring Approaches academic integrity chinese letters of recommendation Anki DO Social Advocacy admissions advice algebra astrophysics business classics diversity statement genetics geometry kinematics linear algebra mechanical engineering mental health presentations quantitative reasoning skills study abroad technical interviews time management work and activities 2L DMD IB exams ISEE MD/PhD programs Sentence Correction adjusting to college algorithms amino acids analysis essay art history artificial intelligence athletics business skills careers cold emails data science dental school finance first generation student functions gap year information sessions international students internships logic networking poetry resume revising science social sciences software engineering tech industry trigonometry 3L AAMC Academic Interest EMT FlexMed Fourier Series Greek Health Professional Shortage Area Italian Lagrange multipliers London MD vs PhD MMI Montessori National Health Service Corps Pythagorean Theorem Python Shakespeare Step 2 TMDSAS Taylor Series Truss Analysis Zoom acids and bases active learning architecture argumentative writing art art and design schools art portfolios bibliographies biomedicine brain teaser campus visits cantonese capacitors capital markets cell biology central limit theorem centrifugal force chemical engineering chess chromatography class participation climate change clinical experience community service constitutional law consulting cover letters curriculum dementia demonstrated interest dimensional analysis distance learning econometrics electric engineering electricity and magnetism escape velocity evolution executive function freewriting genomics graphing harmonics health policy history of medicine history of science hybrid vehicles hydrophobic effect ideal gas law immunology induction infinite institutional actions integrated reasoning intermolecular forces intern investing investment banking lab reports linear maps mandarin chinese matrices mba medical physics meiosis microeconomics mitosis mnemonics music music theory nervous system neurology neuroscience object-oriented programming office hours operating systems organization outlining