Answer:
a^2+b^2=c^2
c=15 units
Explanation:
You can use the pythagorean theorem to solve this equation. a^2+b^2=c^2.
If you substitute the leg lengths in, the new equation will be 9^2+12^2=c^2, c being the hypotenuse.
Next, you can simplify it to get 81+144=c^2. Simplifying it further, you get 225=c^2, which means that the length of the hypotenuse is 15. Hope this helped! :)