Triangle Inequality Rule

Triangle Inequality Rule

One of the less-common but still need-to-know rules tested on the GMAT is the “triangle inequality” rule, which allows you to draw conclusions about the length of the third side of a triangle given information about the lengths of the other two sides. Often times,...
Isosceles Triangles and Data Sufficiency

Isosceles Triangles and Data Sufficiency

Although we’ve already discussed isosceles triangles a bit during our discussion of 45-45-90 (i.e. isosceles right) triangles, it’s worth discussing some other contexts in which you may see isosceles triangles on the GMAT, specifically on Data Sufficiency problems. ...
The 5-12-13 and 7-24-25 Right Triangles

The 5-12-13 and 7-24-25 Right Triangles

By: Rich Zwelling, Apex GMAT Instructor Date: 12th January, 2021 The 5-12-13 and 7-24-25 Right Triangles Although the 3-4-5 right triangle is by far the most common of the so-called “Pythagorean triples” tested on the GMAT, there are a few others worth knowing. First,...
45-45-90 Right Triangle – GMAT Geometry Guide

45-45-90 Right Triangle – GMAT Geometry Guide

By: Rich Zwelling, Apex GMAT Instructor Date: 6th January, 2021 45-45-90 Right Triangle Another of the commonly tested triangles on the GMAT is the 45-45-90, also known as the isosceles right triangle. Know that term, as it could appear by name in a question. As shown...
The 3-4-5 Right Triangle – GMAT Geometry Guide

The 3-4-5 Right Triangle – GMAT Geometry Guide

By: Rich Zwelling, Apex GMAT Instructor Date: 17th December, 2020 Right Triangle Identities: 3-4-5 Right triangles always adhere to the same basic relationship, reflected by the Pythagorean Theorem, or a² + b² = c², where a, b, and c match the triangle sides as...