[挑戰]正三角形內切兩圓 ΔABC is equilateral with side length 4. D is a point on BC such that BD = 1. If r and s are the radii of the inscribed circles of ΔADB and ΔADC respectively, find rs.link...
In ΔABC, AB=AC=13 and BC=10. P is a point on BC with BP<PC, and H,K are the orthocentres of ΔAPB and ΔAPC respectively. If HK=2, find PC.Show your steps with suitable diagram(s)L...