Answer:
? = 1 (assuming right-angled triangle)
Step-by-step explanation:
This is an application of Pythagoras' Theorem, but rearranged:
[tex]a^{2} = c^{2} - b^{2}[/tex]
[tex]\sqrt{10}^{2}[/tex] is, of course, 10, so 10 - 9 = 1, and [tex]\sqrt{1} = 1[/tex].
