In regular pentagon \(PQRST\), X is the midpoint of segment ST. What is the measure of angle XQS in degrees?
Draw QT and QS
Angles TQP, SQT and SQR will trisect the interior angle PQR
And PQR = 108
So ...angle SQT = 108 / 3 = 36
But...by symmetry....angle XQS = (1/2)angle SQT = (1/2)36 = 18°
+885 
