freeCodeCamp/curriculum/challenges/english/10-coding-interview-prep/project-euler/problem-94-almost-equilateral-triangles.md

---
id: 5900f3ca1000cf542c50fedd
title: 'Problem 94: Almost equilateral triangles'
challengeType: 5
forumTopicId: 302211
dashedName: problem-94-almost-equilateral-triangles
---

# --description--

It is easily proved that no equilateral triangle exists with integral length sides and integral area. However, the <dfn>almost equilateral triangle</dfn> 5-5-6 has an area of 12 square units.

We shall define an <dfn>almost equilateral triangle</dfn> to be a triangle for which two sides are equal and the third differs by no more than one unit.

Find the sum of the perimeters of all <dfn>almost equilateral triangle</dfn> with integral side lengths and area and whose perimeters do not exceed one billion (1,000,000,000).

# --hints--

`almostEquilateralTriangles()` should return a number.

```js
assert(typeof almostEquilateralTriangles() === 'number');
```

`almostEquilateralTriangles()` should return 518408346.

```js
assert.strictEqual(almostEquilateralTriangles(), 518408346);
```

# --seed--

## --seed-contents--

```js
function almostEquilateralTriangles() {

  return true;
}

almostEquilateralTriangles();
```

# --solutions--

```js
// solution required
```