Rajah 2 menunjukkan dua bulatan sepusat, $ABC$ dan $DFE$, berpusat di $O$. Garis lurus $AFB$ ialah tangen, pada titik $F$, kepada bulatan dalam itu. Jejari $OA$ dan $OB$ bagi bulatan besar memotong bulatan kecil masing-masing di $D$ dan $E$. Diberi bahawa $OD = 9$ cm dan $AB = 18$ cm. Diberi juga bahawa $OA = 9\sqrt{2}$ cm.
[Guna $\pi = 3.142$]

Kawasan berlorek dibatasi oleh $DA$, garis lurus $AFB$, $BE$ dan lengkok $EFD$ bagi bulatan kecil. Hitung luas kawasan berlorek itu, dalam cm$^2$, dan berikan jawapan anda betul kepada tiga angka bererti.

Diagram 2 shows two concentric circles, $ABC$ and $DFE$, with centre $O$. The straight line $AFB$ is a tangent, at the point $F$, to the inner circle. The radii $OA$ and $OB$ of the larger circle cut the smaller circle at $D$ and $E$ respectively. It is given that $OD = 9$ cm and $AB = 18$ cm. It is also given that $OA = 9\sqrt{2}$ cm.
[Use $\pi = 3.142$]

The shaded region is bounded by $DA$, the straight line $AFB$, $BE$ and the arc $EFD$ of the smaller circle. Calculate the area of the shaded region, in cm$^2$, giving your answer correct to three significant figures.