JSFiddle - React, Tailwind, and code Playground

HTML

<canvas id="mycanvas" width="400" height="250"> </canvas>

CSS

#mycanvas{
            border: 1px solid black;
        }

JavaScript

function dix180(){
     let nb=0;
     while (nb<10){
        nb=Math.round(Math.random()*180);
     }
     return nb
}  
        
function mesureangle(x,y) {
  let x1 = x;
  let y1 = y;
  let length1 = 100;
 
  let angle1 = dix180();
  let angle2 = angle1 + dix180(); 


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

  console.log(angle2-angle1);
 
  // 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.getElementById('mycanvas');
  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();
  ctx.font = "30px Arial";
  ctx.fillText((angle2-angle1).toString() +' °',20,50); 
}

mesureangle(200,125);