Besides making a pie (I’m making this), could I recommend teaching your children the following (you could say it as a rhyme, or if you’re really into it, make up some moves and pretend you are “math” cheerleaders):
tangent! secant! cosine! sine! three point one four one five nine!
Say it out loud and it will make sense. You’ll never forget the value of pi if you know this.
p.s. I knew a lot of nerdy people in high school, but a very cute and un-nerdy boy actually taught me this.