triangle

I have Uaru Amphiacanthoides of all sizes for sale. They are all unsexed. I have Fry at about an inch long that will be available 8/1/22. They will be $25 each. Juveniles that are available now at $25 each. On 8/1/22 they go to $35 each as they're getting big. A group of three adults for $150...

So im considering building a tank for a corner, the questions I have is should I try to make it just a triangle or more of a pentagon? Also how would I know the angles to get the glass / acrylic cut to? as well as what length i would make the 3 viewing panels? I am also clueless of how I would...