30. CHỌN (B). S = 4 Π R2 = 4 Π 52 =4 Π .25 =100 Π CM2.V= 43 Π R3 = ..

4.30. Chọn (B). S = 4

π

r

2

= 4

π

5

2

=4

π

.25 =100

π

cm

2

.

V=

4

3

π

r

3

=

4

3

π

5

3

=

500

3

π

com

3

.