Question

Prove that area of triangle having thita of angle is equal to a*b*sin thita ÷2

Answer 1

let Ф be the angle in pace of Thita
Let angle Ф be formed by sides a & b      
          we know        sinФ= height/a ⇒ height=a* sinФ
We have area of triangle = (height*b )/2                             
                                      = (a*sinФ*b )/2                        
                                      = ( a*b* sinФ)/2