(AC)^2+(AB)^2-(CB)^2
(AC)^2=25-16=9
AC=3
cos(A)=AC/AB=3/5
в=√с²-а²=5²-4²=3
в=с*cos А
cos А=в/с=3/5=0,6
(AC)^2+(AB)^2-(CB)^2
(AC)^2=25-16=9
AC=3
cos(A)=AC/AB=3/5
в=√с²-а²=5²-4²=3
в=с*cos А
cos А=в/с=3/5=0,6