dc^2+ac^2=ad^2 ad^2+bd^2=ab^2将一式带入二式dc^2+ac^2+bd^2=ab^2 ===>dc^2+16+36=ab^2 ===>dc^2+52=ab^2又因ac^2+ab^2=(bd+dc)^2将三式代入四式ac^2+dc^2+52=(bd+dc)^2 ===>16+dc^2+52=(6+dc)^2 ==>dc^2+68=36+12d...