Math.atan()

Math.atan():// 以弧度計算直角三角形的角度

function calcAngle(opposite, adjacent) {
  return Math.atan(opposite / adjacent);
}


console.log(calcAngle(8, 10));
// Expected output: 0.6747409422235527

console.log(calcAngle(5, 3));
// Expected output: 1.0303768265243125