Question Number 193387 by Mingma last updated on 12/Jun/23
Commented by Frix last updated on 12/Jun/23
$$\mathrm{The}\:\mathrm{circle}\:\mathrm{is}\:\mathrm{the}\:\mathrm{circumcircle}\:\mathrm{of}\:\mathrm{a}\:\mathrm{triangle}: \\ $$$${a}=\mathrm{6} \\ $$$${b}=\mathrm{6}\sqrt{\mathrm{7}} \\ $$$${c}=\mathrm{18} \\ $$$$\Rightarrow \\ $$$${R}=\mathrm{2}\sqrt{\mathrm{21}} \\ $$$$\mathrm{Area}\:\mathrm{of}\:\mathrm{the}\:\mathrm{semi}\:\mathrm{circle}\:=\mathrm{42}\pi \\ $$