Question

State and prove Lami's theorem.

Answer 1

α+β+θ=360 from fig (a)

Now consider figure (b)

(180−α)+(180−β)+(180−θ)=180 (SUM of angles of a triangle

So open brackets 180+180+180-(α+β+θ)=180

which gives α+β+θ=360
which is true from figure (a)
hence PQR should be 180-β

Thats all
Thank you
Do like us