If you use a proportion, you'll get:

Then, you use cross products:

Then, you algebraically solve x:

The answer is 5/3 inches , or 1 5/13 inches, or 1.6 repeating.
I solved it on a piece of paper. I can not answer why I got the same answer, but I hope my method helped
Answer: 80
Step-by-step explanation:
Multiple 8 x 10