point O is taken inside of an equal side of a quadilateral ABCD ,all sides are eual such that OB = OD, show that A,O and C are collinear.
Answers
Answer:
ao and oc are in straight line
Step-by-step explanation:
consider triangles DOC and BOC
DO = BO (given)
DC = BC (since all sides are equal)
OC = OC ( common)
by SSS congruency criterion,they are congruent
so, angle DOC = angle BOC ( CPCT ). ----------------1
consider triangles ADO and ABO
DO = OB ( given )
AD = AB ( since all sides are equal )
AO = AO ( common )
by SSS congruency criterion, they are congruent
so, angle AOD = angle AOB (CPCT). --------------------2
angle AOD + angle AOB + angle DOC + angle BOC = 360°(angle at a point is 360°
from 1 and 2,
angle AOD + angle AOD + angle DOC + angle DOC = 360°
2 angle AOD + 2 angle DOC = 360°
2( angle AOD + angle DOC) = 360°
angle AOD + angle DOC = 180°
so they form a linear pair
therefore, AO and OC are in one and the same straight line.