I know one teacher who went through the first month of her geometry class talking about the "hippo-tense" of a triangle before somebody corrected her.
What's really needed, as a minimum, is a requirement that the teacher have passed, with a B or better, a college level algebra course. I'm talking about a real math course, not "math for educators".
I had a high school biology teacher who was completely secure in his rightness regarding the meanings of “voluntary” and “involuntary,” despite having them completely backwards. He would brook no attempted correction at all. I should know, I tried and earned a trip to the principal’s office for it, lol. For all I know, he’s still teaching it incorrectly, if he’s still teaching.
-——”hippo-tense”——
The sqaw of the hippopotamus is equal to the some of the sqaws of the other two hides
Well, you really don't need that hippo-tense junk if you know how to make a 3-4-5, or 6-8-10 corner.
I've turned over dirt for many years, and I've never seen a square root.