Answer:
Using the "Pythagorean Theorem" formula:
a^2 + b^2 = c^2 we can find the hypotenuse of this triangle.
Replace the values of a, b, and c with it's actual values;
8^2 + 4^2 = __^2 ← our missing value
64 + 16 = 80, now we need to find the square root of 80:
√80 = 8.944, which equals to around 8.9.
so to rewrite:
8^2 + 4^2 = 8.9^2, so 8.9 is your answer.