Answer:
½pi or 0.5pi units²
Step-by-step explanation:
Area : angle
9pi : 2pi
x : pi/9
9pi/2pi = x/(pi/9)
4.5 × pi/9 = x
x = ½pi or 0.5pi units²
idk
4
7.071 cm
.125 for 1 button
6 dollars for 48 buttons