In the adjoining figure, show that +++++=360°

Proof


In triangle BDF,


++ = 180°[Sum of angles of triangle] _______________ (i)


In triangle BDF,


++ = 180°[Sum of angles of triangle] _______________ (ii)


From equation (i) and (ii),


(++) + (++) = (180°+180°)


+++ ++ = 360°Proved.


21