Respuesta :

calculista
we know that
in the right triangle PQR
sin 51°= opposite side angle 51°/hypotenuse

opposite side angle 51°=QR
hypotenuse=17 cm
so
sin 51°=QR/17------> QR=17*sin 51°-----> QR=13.21 cm-----> QR=13.2 cm

the answer is
QR=13.2 cm