Do the measurements given below denote the angles of a triangle?

$30°, 50°, 90°$

Do the measurements given below denote the angles of a triangle?

$52°, 52°, 76°$

In $△PQR$, $PS\perp QR$, if $\angle QPR=60°$ and $\angle R=50°$, find $\angle RPS$ and $\angle PQS$.

In the given figure, $l\parallel m$, if $QP\perp l$ and $SR\perp l$ and $PQ=3.5 cm$, find $SR$.

Draw all the three altitudes of the given $△ABC$.