Jawabanmu

2014-04-13T09:46:19+07:00
Luas segi n beraturan,

L = ½ r² n sin (2π/n)

192 = ½ r² * 12 sin (2π/12)

r = 8 cm


keliling segi n beraturan,

K = r n√(2(1 - cos (2π/n)))

K = 8 * 12 √(2(1 - cos (2π/12)))

K = 49.693256659683986371 cm