(1)
Solve the following triangles, answers of angle correct to 1’, sides correct to 2 decimal places.
解下列各三角形， 其答案角度准确到1’, 边长准确到小数2位数。
(a) A = 40
, B = 70, a = 7
(b) A = 35, B = 60, c = 5
(c) a = 6, b = 4, B = 30
(d) a = 5, b = 7, A = 30
(e) a = 5, b = 7, A = 60
答案 Answer :
(a) C = 70, b = 10.23, c = 10.23
(b) C = 85, a = 2.88, b = 4.35
(c) A = 4835’, C = 10125’, c = 7.84 or A = 13125’, C = 1835’, c = 2.55
(d) B = 44.43, C = 105.57, c = 9.63 or B = 135.57, C = 14.43, c = 2.49
(e) 无解
(2)
In 
ABC, (a + b) : (b + c) : (c + a) = 3 : 4 : 5, find sinA : sinB : sinC.
在 ABC中, (a + b) : (b + c) : (c + a) = 3 : 4 : 5, 求 sinA : sinB : sinC.
答案 Answer :
2 : 1 : 3
(3)
If the angles of a triangle are in a ratio 1 : 6 : 3, and the perimeter of the triangle is 100cm, find the length of three sides.
若三角形的角的比例为1 : 6 : 3, 且该三角形的周长是 100cm，求三边长。
答案 Answer :
14.93cm， 45.97cm，39.10cm