Answer:
[tex]a=\sqrt{63}[/tex]
Step-by-step explanation:
When we solve for this we should always remember this formula [tex]a^2+b^2=c^2[/tex] and since we already know b and c we can plug that in tho find out what a could be but we won't actually solve it.
[tex]a^2+b^2=c^2\\a^2+9^2=12^2\\a^2+81=144\\a^2=63\\\sqrt{a^2}=\sqrt{63}[/tex]
So a would equal whatever the square root of 63 is.
