bagaimana caranya , please beri tahu caranya ya dan jawabannya

[tex]l \: ling = \pi {r}^{2} \\ = \frac{22}{7} \times 63 \times 63 \\ = 12474 {cm}^{2} [/tex]
[tex]l \: yg \: diarsir \\ = \frac{120}{360} \times 12474 = 4158 {cm}^{2} [/tex]
moga tak keliru