JSFiddle - React, Tailwind, and code Playground

HTML

<canvas class="canvas"></canvas>

JavaScript

mesureangle('canvas');

function mesureangle(a) {
  let x1 = 50;
  let y1 = 50;
  let length1 = 200;

  let angle1 = Math.floor(Math.random() * 181) + 180;
  let angle2 = angle1 + Math.floor(Math.random() * 181);

  // Convertir les angles en radians
  let angleRad1 = (angle1 * Math.PI) / 180;
  let angleRad2 = (angle2 * Math.PI) / 180;

  // Calculer les coordonnées de la première ligne
  let x2 = x1 + length1 * Math.cos(angleRad1);
  let y2 = y1 + length1 * Math.sin(angleRad1);

  let x3 = x1 + length1 * Math.cos(angleRad2);
  let y3 = y1 + length1 * Math.sin(angleRad2);

  let canvas = document.querySelector('.' + a);
  let ctx = canvas.getContext("2d");

  ctx.beginPath();
  ctx.moveTo(x1, y1);
  ctx.lineTo(x2, y2);
  ctx.stroke();

  ctx.beginPath();
  ctx.moveTo(x1, y1);
  ctx.lineTo(x3, y3);
  ctx.stroke();
}