3. In Fig. 6.15, PQR =
PRQ, then prove that
PQS =
PRT.
Given that,
ABC is a triangle such that PQR =
PRQ and ST is a straight line.
Now, PQR +
PQS =
{Linear pair}............(i)
Similarly, PRQ +
PRT =
..................(ii)
equating the eq (i) and eq (ii), we get
{but
PQR =
PRQ }
Therefore, PQS =
PRT
Hence proved.