Finding Corner Mullion Length with Grasshopper

Hello, everyone! I’m trying to find a function of x given values of a, L, and d as in the picture. I thought it was L/Sin(a/2), but it’s weird as in the picture.

사진과 같이 a, L, d 의 값이 주어졌을 때 x의 함수를 구할려고 한다. 나는 L/Sin(a/2)라 생각했는데 사진처럼 이상하게 되네.

yes, that’s correct: x = L / Sin(a/2)

What is the problem?

I want to make line like this picture.