Jawabanmu

2014-08-19T17:59:11+07:00
Luas kulit bola = 4 * 22/7 *  (10.5 )_{2} = 1.386
2014-08-19T17:59:12+07:00
Luas = 4 x π r²
 = 4 x \frac{22}{7} 10,5 10,5
 = 1386