Answer:
12.04
Explanation:
Well to solve for the unknown side "c" we need to use the Pythagorean Theorem formula,

We already have a and b which are 8 and 9 so we plug them in.

64 + 81 = c^2
145 = c^2
c = 12.04 rounded to the nearest hundredth.
Thus,
the unknown side is about 12.04.
Hope this helps :)