r = 9
h = 36
Pp = ?area of a circle
l = ? surface of the wheel
Pb = lateral surface
Pc - total surface
Pp = πr² = 9²*π = 81π (unit²)
l = 2πr = 2*9*π = 18π (unit)
Pb = l*h = 18π * 36 = 648 π(unit²)
Pc = 2Pp + Pb = 2* 81π + 648π = 162π + 648π = 810π(unit²)
Answer total area equal to 810π (unit²)