Jawabanmu

2014-04-18T21:45:46+07:00
1/3. 22/7. r².10,5= 2156
r²=2156x7/22 :(10.5x 1/3)
r²= 2156 : 3,5 x 22/7
r²= 196
r= 14

L permukaan= Luas selimut + Luas alas
L.p= 22/7.14.10,5 + 22/7.14.14
L.p= 462 + 616=1078