Answer:
the missing leg length is 2√70.
Explanation:
This is a right triangle in which the hypotenuse is 19 ft and one of the legs is 9 ft. Using the Pythagorean Theorem, we find the length of the other leg:
x^2 = (19 ft)^2 - (9 ft)^2 = 361 - 81 = 280, or 4*70
Then the missing leg length is √4√70, or 2√70.