31. CHỌN (D).SXQ=2 Π R H = 2 Π .6.8=96 Π CM2.STP = SXQ + 2SĐÁY = 96...
4.31. Chọn (D).
S
xq
=2
π
r h = 2
π
.6.8=96
π
cm
2
.
S
tp
= S
xq
+ 2S
Đáy
= 96
π
+ 2(
π
.6
2
) = 96
π
+ 72
π
= 168
π
cm
2
.
V=
π
r
2
h =
π
.6
2
.8 = 288
π
cm
3