Question

в треугольнике ABC угол c равен 90,AB=12,tg a = 5/корень из 20. найдите Ac.

Answer 1

AC^2+BC^2=AB^2=144
BC/AC=tgA; AC^2=BC^2/(25/20)=20BC^2/25
20BC^2/25+BC^2=144
45BC^2=3600
BC^2=80
BC=4√5 AC=√20*80/25=8