Solution
# If you're just opening your home page
if request.method == "GET":
return render_template('index.html')
# If you submitted one of the forms
elif request.method == "POST":
if request.values.get("action", None) == 'Calculator':
return render_template('/densitycalc.html')
elif request.values.get("action2", None) == 'Linear Feet':
return render_template('/linearFeet.html')
elif request.values.get("action3", None) == 'Insurance':
return render_template('insurance.html')
elif request.values.get("action4", None) == 'Home':
return render_template('index.html')