Jawabanmu

2014-05-09T14:35:48+07:00
luas juring =  \frac{x}{360} X  π  r^{2}
=  \frac{45}{360} x 3,14 x 12 x 12
 \frac{1}{8} x 3,14 x 144
= 56,52  cm^{2}
2014-05-09T14:45:35+07:00
Luas juring = α/360 x phi x r²
luas juring = 45/360 x 3,14 x 12²
luas juring = 1/8 x 3,14 x 144
luas juring = 1/8 x 452,16
luas juring = 452,16/8
luas juring = 56,52 cm²