BodhiAI
Nov. 12, 2019

#### Projection Rule:

Projection Rule

In any ΔABC a = b cos C + c cos B

b = c cos A+ a cos C

c = a cos B + b cos A

Trigonometrical Ratios of Half Angles of a Triangle

Since,

Similarly,

and

again

Also,

Similarly,

and

From above cases, we can say that