Answer:
15
Step-by-step explanation:
Hello There!
We can find the missing side length using the Pythagorean theorem
The Pythagorean theorem states that the sum of the two legs squared equal the hypotenuse squared
so now we want to make an equation using the Pythagorean theorem
let c^2 be missing side length
[tex]12^2+9^2=c^2[/tex]
now we can solve
[tex]12^2=144\\9^2=81\\81+144=225\\225=c^2\\\sqrt{225} =15\\\sqrt{c^2} =c\\c=15[/tex]
So we can conclude that the length of the missing side is 15
