Solution Of Triangles

Question 1

What is Sine Rule ?

Answer 1

In any triangle ABC, sines of angles are proportional to the opposite sides ie
(a/sin a)= (b/sin b)= (c/ sin c)

Question 2

Cosine formula.

Answer 2

Cos A= (b^+c^-a^)/2bc
Cos B= (c^+a^-b^)/2ca
Cos C= (a^+b^-c^)/2ab

Question 3

Projection formula.

Answer 3

In Triangle ABC, sides a,b,c
a= b cos C+ c cos B
b= c cos A+ a cos C
c= a cos B + b cos A

Question 4

Napiers analogy( tangent rule )

Answer 4

Tan(B-C)/2 =b-c/b+c cotA/2
Tan (C-A)/2= c-a/c+a cot B/2
Tan (A-B)/2 = a-b/a+b cot C/2