Answer:
72/25
cm² or 9.047786842... cm²
Explanation:
Area of whole circle is
×2.4² = 144/25
cm² or 18.09557368... cm²
Since it is a semi-circle, divide this value by 2 (or multiply by 0.5, either way, your halving it):
144/25
÷ 2 = 72/25
cm² or 9.047786842... cm²