Panjang AB=BC dan keliling daerah yg diarsir 55cm. Panjang AB=...cm

[tex]21 \div 3 = 7 \\ \frac{22}{7} \times 7 = 22 \\ \frac{1}{2} \times 21 \times 21 = 220 \\ 220 - 22 = 198[/tex]