Diet Key Lime Pie

3-ounces sugar-free lime gelatin
1/4 cup boiling water
3 cartons (6 ounces each) key lime yogurt
6 ounces whipped topping
1 graham cracker pie crust
1/4 cup boiling

Mix gelatin and boiling water until dissolved. Wait five minutes. Add the yogurt and mix well. Add the whipped topping and mix well. Pour into the pie crust and refrigerate for four hours.