See the attached picture to better understand the problem
we know that
in the right triangle ABC
sin 63°=AB/BC
AB is the opposite side angle 63-----> x cm
BC is the hypotenuse-----> 85 cm
AB=BC*sin 63°-----> AB=85*sin 63-----> AB=75.736 cm
AB=75.8 cm
the answer is
the value of x is 75.8 cm
we know that
in the right triangle ABC
sin 63°=AB/BC
AB is the opposite side angle 63-----> x cm
BC is the hypotenuse-----> 85 cm
AB=BC*sin 63°-----> AB=85*sin 63-----> AB=75.736 cm
AB=75.8 cm
the answer is
the value of x is 75.8 cm