Втреугольнике abc угол c равен 90 градусов,bc=4,8, cos a =7: 25. найдите ab.

Sin A = BC/AB
AB = BC/sin A
sin A = (1-cos^2 A)^(1/2) = (1-49/625)^(1/2)=(576/625)^(1/2)=24/25
AB = 4,8:24/25=4,8*25/24=5