Question

Hemispheres P and Q have their radii 30cm and 10cm respectively. The ratio of total surface area of sphere P to sphere Q is

Answer 1

T. S. A of hemi sphere = 2πr^2

T. S. A α r^2

r(1)=30

r(2)=10

r^2(1)/r^2(2)= 30^2/10^2

= 900/100=9:1