答：设斜边为c=40,直角边为a和b,锐角A=15°cos30°=1-2sin²15°=√3/2解得：sin15°=(√3-1)/(2√2)（负值不符合舍去）cos15°=(√3+1)/(2√2)则：a=csinA=40sin15°=10(√6-√2)厘米b=ccosA=40cos15°=10(√6+...