How Many Sides Does a "Pizzagon" Have?

I spent shabbat with my friends who have the 3rd cutest child ever! Of course my niece and nephew are 1st and 2nd. If I could figure out how to put pix on this thing successfully, I would prove it. Also if my sister had a camera, like any normal parent, then I would have pictures to upload. But as the perfect aunt, of course I have a camera with tons of pictures - and video - of my cutest niece and nephew. But I digress.
I spent shabbat with Hana and I had conversations I just never thought I would have as a woman in my 20's. "are you done with your doo-doo? I'm waiting for you to finish your doo-doo." and "I make shi-shi." "wow! you made shi-shi?! good girl!" Not exactly word for word, but you get the idea.
So we were playing with one of those balls with the different shaped holes and you have to put the different shaped blocks in the correct matching shaped holes. You know what I'm talking about. You all had one. Most of the shapes have specific names, like square, circle, hexagon, plus sign, star, etc. and Hana knows all the shapes names, including the hard ones that most people don't learn until 10th grade geometry. So we're putting the shapes into the holes and she says what each one is - "square...circle...plus sign....star....pentagon....pizzagon...." I stopped and asked what a "pizzagon" is. She showed me. It's the shape that's like a triangle, but has a round bottom instead of a straight line. So it looks like 1/4 of a pizza. That is a "pizzagon". They don't teach you that in 10th grade. So now you know.