I found out my school uses Springboard Geometry: Texas Edition as the geometry textbook, but I can’t really find this anywhere. Anyone have a clue?
I’m guessing you’ve looked on Amazon, etc., right? You could also ask your local library if they can get it as an inter-library loan. Have you asked your teacher if she can provide an online link to the book? All DD’s textbooks are online this year.
if you have a ISBN number it might help you search comparison sites such as bigwords.com
What does your math teachers say? I imagine that if they’re going to assign a text, they probably have the resources to tell you where to get it.
I’m not in the class, I just want the book for self-study. Shall I ask my counselor for the ISBN?
Ask the teacher since it’s their class
You could still contact the department chair.
Or simply use another textbook. I love teaching Geometry. My favorite text is the Dressler Geometry book, published by Amsco (ISBN978-1-56765-560-5 It’s probably out of print, but you can get it used-- and Geometry hasn’t changed all that much in the past few years.
ETA-- I just checked. You can get it used on Amazon for under $5.
try https://www.bartleby.com/subject/math or textbooks.com ! they usually have everything i need
@bjkmom, I wish I could have asked you for a geometry textbook recommendation when my middle son was in 10th grade. His teacher was really poor - she was close to retirement age and just didn’t care. DS was struggling and we asked for supplemental texts. She replied that she was using curriculum developed by other faculty and she couldn’t give us any suggestions for other material! My husband was shaking, he was so furious as we walked out of a meeting with her. 
Thank goodness she retired the next year.