Answer: c = 8 yards
Work Shown:
cos(angle) = adjacent/hypotenuse
cos(45) = c/(8*sqrt(2))
c = 8*sqrt(2)*cos(45)
c = 8*sqrt(2)*(1/sqrt(2))
c = 8
----------------
Optionally, you can use the 45-45-90 triangle template which says that the length of the leg of this triangle is x and the hypotenuse is x*sqrt(2)
Since 8*sqrt(2) is the given hypotenuse, this must mean x*sqrt(2) = 8*sqrt(2) so x = 8