Mathematics is a compulsory course for senior one. In triangle abc, the following conditions are known to solve triangle 1, a = 70°C = 30°C = 20 cm2, a = 34° B = 56°C = 68cm.
1).b = 180-A-C = 180-70-30 = 80 .a/SinA=c/SinC， a = cSinA/SinC = 20 sin 70/sin 30 = 37.58…≈38 .b = cSinB/SinC = 20 si 80/sin 30 = 39.39……≈39 .2).A-B= 180-34-56=90 .SinA=a/c，a=cSinA=68Sin34=38.02…=38 .b=cCosA=68Cos34=56.37…≈56 .