---
id: 5900f43e1000cf542c50ff50
challengeType: 5
title: 'Problem 210: Obtuse Angled Triangles'
---
## Description
Consider the set S(r) of points (x,y) with integer coordinates satisfying |x| + |y| ≤ r.
Let O be the point (0,0) and C the point (r/4,r/4).
Let N(r) be the number of points B in S(r), so that the triangle OBC has an obtuse angle, i.e. the largest angle α satisfies 90°<α<180°.
So, for example, N(4)=24 and N(8)=100.
What is N(1,000,000,000)?
## Instructions
## Tests
```yml
tests:
- text: euler210() should return 1598174770174689500.
testString: 'assert.strictEqual(euler210(), 1598174770174689500, "euler210() should return 1598174770174689500.");'
```
## Challenge Seed
```js
function euler210() {
// Good luck!
return true;
}
euler210();
```