Question

Find the surface areas and volumes of sphere of the following radii.
(i) 4 cm (i) 9 cm (11) 3.5 cm.
Pi is equal to 3.14 ​

Answer 1

$\huge\mathfrak\red{Solution}$

Using the formula

$\huge{\boxed{Surface \:area \:of\: sphere = 4\pi{r}^{2}}}$

(1.) 4cm

surface area of sphere = 4πr²

surface area of sphere = 4 × 3.14 × 4 × 4

= 64 × 3.14

surface area of sphere = 200.96cm²

(2) 9cm

Surface area of sphere = 4πr²

= 4 × 3.14 × 9 × 9

= 4 × 3.14 × 81

Surface area of sphere = 1017.36cm²

(3)3.5

Surface area of sphere = 4πr²

= 4 × 22/7 × 3.5 × 3.5

= 4 × 22 × 0.5 × 3.5

Surface area of sphere = 154cm²

Answer 2

Answer:

I) 4cm

Surface area of sphere =4πr²

=4×3.14×4×4

=200.96cm²

Volume of sphere=4/3×πr³

=4/3×3.14×4×4×4

=803.84/3

=267.9cm³

II) 9cm

Surface area of sphere =4πr²

=4×3.14×9×9

=1017.36cm²

Volume of sphere=4/3×πr³

=4/3×3.14×9×9×9

=91564/3

=3052.08cm³

III)3.5cm

Surface area of sphere =4πr²

=4×3.14×3.5×3.5

=153.86cm²

Volume of sphere=4/3×πr³

=4/3×3.14×3.5×3.5×3.5

=538.514/3

=179.59cm³