Answer:
a = 254.5 mm² ( if using accurate value of π)
a = 254.4 mm² (if using 3.14 as approximate value of π)
Explanation:
a = πr²
a = π * 9²
a = π * 81
(note using π = 3.1415926536)
a = 254.4690049408
Rounded
a = 254.5 mm²
(a = 254.4 If using π = 3.14)