A regular decagon is inscribed in a circle with radius 8. Which of the following is the length of one of its sides?

W) 8 sine of 36\({}^{\circ}\)

X) 8 cosine of 36\({}^{\circ}\)

Y) 16 sine of 18\({}^{\circ}\)

Z) 16 cosine of 18\({}^{\circ}\)
Y) 16 sine of 18\({}^{\circ}\)