Question

В треугольнике ABC угол C равен 90º,AB=25,cosB=4/5.найдите AC

Answer 1

Cos^2 + sin^2 = 1
sin^2=1-cos^2
sin^2=1 - 16/25
sin^2= 9/25
sin = 3/5
sin B = AC/AB = 3/5
AC=AB*3/5
AC=25*3/5
Ac=15