Use the geometric mean for right triangles here to solve for your unknown. Set it up like this: [tex] \frac{16}{x}= \frac{x}{9} [/tex]. Cross multiply to get [tex] x^{2} =144[/tex]. x will equal both +12 and -12, but of course we know that the 2 things in math that will NEVER be negative are time and distance/length. So the length we want is 12. First choice above.
