做AF垂直BC于F,做DE垂直BC于E;
角B=30,则AF=AB/2=5;BF=5√3;
AFED是矩形,则AD=EF=10,AF=DE=5;
DC坡比=1:1.4,即DE:EC=1:1.4;则EC=5*1.4=7
即BC=BF+EF+EC=5√3+10+7=17+5√3≈25.66
做AF垂直BC于F,做DE垂直BC于E;
角B=30,则AF=AB/2=5;BF=5√3;
AFED是矩形,则AD=EF=10,AF=DE=5;
DC坡比=1:1.4,即DE:EC=1:1.4;则EC=5*1.4=7
即BC=BF+EF+EC=5√3+10+7=17+5√3≈25.66