Formas7.html

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Area do circulo</title>
    <script>
const PI=3.14;//Constante PI
var raio=prompt("Digite o valor do raio");
var area=(PI*raio*raio);
alert("O valor da Area do circulo é : " + area);

    </script>
</head>
<body>
    
</body>
</html>