let a
let b
let c
a = window.prompt("Enter side A") // 10
a = Number(a)
b = window.prompt("Enter side B") // 10
b = Number(b)
c = Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2));
console.log("side C:" , c)
result: side C: 14.142135623730951
Html
<label> id="aLabel" for="">Side A:</label>
<input> type="text" id="aTextBox">
<label> id="bLabel" for="">Side B:</label>
<input> type="text" id="bTextBox">
<button> type="button" id="submitButton">submit<button>
<label> id="cLabel" for="">Side C:</label>
Javascript
let a
let b
let c
document.getElementById("submitButton").onclick = function(){
a = document.getElementById("aTextBox").value
a = Number(a)
b = document.getElementById("bTextBox").value
b = Number(b)
c = Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2))
document.getElementById("cLabel").innerHTML = "Side C: " + c
}
Monitor result ⬇️