(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 = 3, b = 6, c = 8
(b) a = 10, b = 8, C = 30
Answer 答案：
(a) A = 18.57, B = 39.56, C = 121.87
(b) C = 5.04, B = 52.53, A = 97.47
In triangle ABC, the lengths of the sides AB, BC and CA are 7cm, 2cm and b cm respectively, and the size of angle C is 30. Use the cosine formula to show that 
, and hence find the exact value of b. Hence, or otherwise, show that 
在三角形 ABC, AB, BC 和 CA 的边长分别为 7cm, 2cm and b cm, 及角C 为 30. 用余弦定律证明 , 据此求 b 的准确值. 据此或其他方法，证明
Answer 答案：
, 
, find 
, 
.
Answer 答案：
, 135(4)
Given that BD = 15, AB = 16, AD = 10 and 
BDC = 30; find the angle of A and the length of BC.
已知BD = 15, AB = 16, AD = 10 和 BDC = 30; 求角A 和BC的长度.
Answer 答案：
65.83, 8.22
(5)
In
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, the lengths of the sides are three consecutive integers, the greatest angle is twice that of the least, find the lengths of sides of the triangles.
在
*** QuickLaTeX cannot compile formula: \bigtriangleupABC *** Error message: Undefined control sequence \bigtriangleupABC. leading text: $\bigtriangleupABC
ABC ，其边长为三连续整数，最大的角是最小的两倍，求三边长。
（提示：
）
Answer 答案：
4, 5, 6
In a triangle 
, 
. Show that triangle is a right angle triangle or isosceles triangle.
在三角形, .，试证三角形是一个直角三角形或等腰三角形。