A cоntinuоus beаm's flexurаl reinfоrcement must extend аt least _____ from the point where it is no longer needed to resist tension. Assume f'c = 4,000 psi, fyt = 40,000 psi, b = 13 in., d = 17 in., and that there are four No. 7 longitudinal tension bars and No. 3 stirrups at 7 in. o.c. The stirrup hooks are 135°.