need help changing excel formula to javascript for medication order form

The problem with translating such an Excel formula is that the round function is different in JavaScript. I would solve the problem like this (the following assumes that there are never any negative results):

var E6 = this.getField("Ht").value;
var G6 = this.getField("Wt").value;
var v = Math.pow(0.007184 * E6, 0.725) * Math.pow( G6, 0.425);
if (v < 10.0) {
    // round to two decimal places
    event.value = Math.round(v * 100) / 100;
}
else if (v < 100.0) {
    // round to one decimal
    event.value = Math.round(v * 10) / 10;
}
else {
    // round to the nearest integer
    event.value = Math.round(v);
}

You would use this as your custom calculation script in your result field.

All of the methods you need to use are described here:

JavaScript Math Reference

JavaScript String Reference

General tutorial about calculations in Acrobat: https://acrobatusers.com/tutorials/how-to-do-not-so-simple-form-calculations