在三角形abc中,b=26cm,c=15cm,C=23°求解三角形 由正弦定理可知c/sinC=b/sinB15/sin23°=38.39sinB=26/38.39=0.68B=43° 或B=137°A=114° A=20°a=35 a=13（都...第二，三题有过程吗a/sinA=b/sinBsinB=b*sinA/a=0.58B=35°C=180°-60°-35°=85°c^2=a^2+b^2-2abcosC =225+100-2*15*10*0.996 =289c=17