notam BC=a
a+5a/6+5a/6=64
6a+10a=384
16a=384
a=24 cm
AB=AC=5×24/6=20 cm
b) p=64/2=32
Aria=S=√p(p-a)(p-b)(p-c)=√32(32-24)(32-20)(32-20)=√(32×8×12×12)=192 cm²
c)Aria=S=AC×BE/2
192=20×BE/2
BE=192×2/20=19,2 cm
d)R=abc/4Aria=(20×20×24)/(4×192)=9600/768=12,5 cm