diketahui luas suatu lingkaran 1,386cm² hitunglah A.diameter lingkaran B.keliling lingkaran

[tex]luas = \frac{1}{4} \pi {d}^{2} \\ 1386 = \frac{1}{4} \times \frac{22}{7} {d}^{2} \\ 1386 = \frac{22}{28} {d}^{2} \\ \frac{22}{28} {d}^{2} = 1386 \\ {d}^{2} = \frac{1386}{ \frac{22}{28} } \\ {d}^{2} = 1386 \times \frac{28}{22} \\ {d}^{2} = 1764 \\ d = \sqrt{1764} \\ d = 42[/tex]
Keliling lingkaran
[tex]k = \pi \times d \\ k = \frac{22}{7} \times 42 \\ k = 132[/tex]
Semoga dapat dipahami