Question

△ABC的内切圆半径为R △ABC的周长为L 求△ABC的面积

Answer 1

设圆心为O,连接AO,BO,CO
S△ABC=S△AOC+S△BOC+S△AOB
=(AB+AC+BC)*r/2
=1*r/2
=r/2

Answer 2

面积S=πR²

Answer 3

设圆心为O,连接AO,BO,CO
S△ABC=S△AOC+S△BOC+S△AOB
=(AB+AC+BC)*r/2
=l*r/2
=r/2*l