9th mathematics NCERT exercise questions with answers, Mathematics

Surface Area and Volumes – Exercise 13.4 – Class IX

Assume π = 22/7 , unless stated otherwise. Find the surface area of a sphere of radius: (i) 10.5 cm (ii) 5.6 cm (iii) 14 cm Solution: (i) r = 10.5 cm Surface area of the sphere  = 4πr2 = 4 x 22/7 x (10.5)2 = 1386 cm2 (ii) r = 5.6 cm Surface area… Continue reading Surface Area and Volumes – Exercise 13.4 – Class IX