由勾股定理求出斜边BC^2=15*15+13*13=394
BC=19.849433241279207869170465726291
三角形ABC面积:0.5*AB*AC=0.5*BC*AD
AD=AB*AC/BC=13*15/19.849433241279207869170465726291
=9.8239580762676282601224386208802
由勾股定理求出斜边BC^2=15*15+13*13=394
BC=19.849433241279207869170465726291
三角形ABC面积:0.5*AB*AC=0.5*BC*AD
AD=AB*AC/BC=13*15/19.849433241279207869170465726291
=9.8239580762676282601224386208802