C++ Pythagorean Theorem

#include <iostream>
#include <cmath>

int main () {
    using namespace std;

    double cathetus_1, cathetus_2;
    cout << "Inserire cateto 1 e cateto 2: ";
    cin >> cathetus_1 >> cathetus_2;

    double hypotenuse;
    // Method 1
    // Applying the Pythagorean theorem
    hypotenuse = sqrt (
        ( cathetus_1 * cathetus_1 )
        + ( cathetus_2 * cathetus_2 ) );

    // Method 2
    // Applying the Pythagorean theorem
    hypotenuse = sqrt (
        pow ( cathetus_1, 2 )
        + pow ( cathetus_2, 2 ) );

    // Method 3
    // Applying the Pythagorean theorem
    hypotenuse = hypot ( cathetus_1, cathetus_2 );

    cout << hypotenuse << endl;

    return 0;
}