Question

Question 1
Find the surface area of a sphere of radius:

(i) 10.5 cm

(ii) 5.6 cm

(iii) 14 cm

$[Assume\pi =\frac{22}{7}]$

Answer 1

(i)
Radius (r) of the sphere = 10.5 cm

Surface area of the sphere $=4\pi r^2$

$=[4\times \frac{22}{7}\times (10.5{)}^2]c{m}^2=(4\times \frac{22}{7}\times 10.5\times 10.5)c{m}^2=(88\times 1.5\times 10.5)c{m}^{2}1386c{m}^2$

(ii)
Radius (r) of the sphere = 5.6 cm

Surface area of the sphere $=4\pi r^2$

$=[4\times \frac{22}{7}\times (5.6{)}^2]c{m}^2=(88\times 0.8\times 5.6)c{m}^2=394.24c{m}^2$

(iii)
Radius (r) of the sphere = 14 cm

Surface area of the sphere $=4\pi r^2$

$=[4\times \frac{22}{7}\times (14{)}^2]c{m}^2=(4\times 44\times 14)c{m}^2=2464c{m}^2$