jari jari lingkaran sama dengan log a2 , keliling lingkaran log b. berapakah nilai 1÷3×log a×b2

[tex]l = log( {a}^{2} ) \\ \pi { r}^{2} = 2 log(a) \\ log(a) = 0.5\pi {r}^{2} \\ k = log(b) \\ log(b) = 2\pi \: r \\ \frac{1}{3 log(a {b}^{2} ) } \\ \frac{1}{3( log(a) + 2 log(b)) } \\ \frac{1}{3( \frac{\pi {r}^{2} }{2} + 4\pi \: r)} [/tex]