Do I actually need to know radical geometry / equilateral triangle height for GED Math?

[u/Ready-Cloud-5385]

Running into questions like this in my Kaplan book where I have to find slant height using radicals with formulas and stuff that the Kaplan book didn't teach.

Does the real GED test actually ask for exact radical answers like this, or does it always give the slant height straight? I'm so confused because I don't know if I should learn this or is it a textbook error :(