2題(sine and cosine formula)

1Solve the triangle PQR with p=32,q=49 ,∠P=36o
(there are two possible set of solution)

sin∠Q/q =sin∠P /p
sin∠Q/49 =sin36o /32
sin∠Q=(49sin36o)/32
∠Q=64.2o or ∠Q=115.8o

∠R=180o-64.2o-36o or ∠R=180o-115.8o-36o
∠R=79.8o or ∠R=28.2o

r/sin∠R =p/sin∠Po
r/sin79.8o=32/sin36o or r/sin28.2o =32/sin36o

r=53.6 or r=25.7



2
In △XYZ ,y=7,z=11 and ∠Z=48o.Find ∠Y

sin∠Y/ y = sin∠Z /z
sin∠Y/ 7 = sin48o /11
sin∠Y=(7sin48o )/11
Y=28.2o or 151.8o



2009-05-21 16:40:38 補充：
151.8度(reject)