apa rumus lingkaran?

D = 2×r
K = 2π×r
A = πr²
Semoga Membantu

[tex]k = 2\pi \times r \\ l = \pi \times {r}^{2} \\ p.busur = \frac{ \alpha }{360} \times k.lingkaran \\ l.juring = \frac{ \alpha }{360} \times l.lingkaran \\ < pusat = 2 keliling \\ < keliling = \frac{1}{2} \times < pusat \\ tembereng = l.juring - l.segitiga[/tex]