Hi,

No, I'm not taking about angle brackets like rangle. I'm talking about the angle symbol usually referring to triangle angles -- searching rightangle on https://www.google.com/url?sa=t&source=web&rct=j&url=http://tug.ctan.org/info/symbols/comprehensive/symbols-a4.pdf&ved=2ahUKEwihjoLM79TpAhVLrp4KHZebCHYQFjABegQIBBAI&usg=AOvVaw3ky1kdqfxipxMYN9L1RjP-&cshid=1590611043073 should make it clear -- you don't need stix just the fdsymbol package.