TRIANGLES | EXTERIOR ANGLE OF A TRIANGLE, CONGRUENCE, CONGRUENCE OF LINE SEGMENTS, CONGRUENCE OF ANGLES | Exterior angle theorem : If a side of a triangle is produced; the exterior angle so formed is equal to the sum of the two interior opposite angles., The sides AB and AC of a `Delta ABC` are produced to P and Q respectively. If the bisectors of `/_PBC` and `/_QCB` meet at O ; Then `/_BOC = 90^@ - 1/2 /_A`, The sides BC;CA and AB of a `Delta ABC`; are produced in order; forming exterior angles `/_ACD;/_BAE and /_CBF`. Show that `/_ACD + /_BAE + /_CBF = 360^@`, Congruence of Line segments, Congruence of Angles, Congruence of Triangles, Congruence relation