This question was asked in 2012 cbse board exam. Question from RS Aggarwal book chapter volume and surface area of solid, page number 829, exercise 17D, problem number 35
Deepak BoraNewbie
A toy is in the form of a cone of radius 3.5 cm mounted on a hemisphere of same radius. The total height of the toy is 15.5 cm. Find the total surface area of the toy.
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ht of toy=15.5 cm (given)
ht of hemisphere=3.5 cm
ht of cone=15.5-3.5
=12cm
slant ht. of cone=under root h^2+r^2
=under root (12^2+3.5^2)
=under root 144+12.25
=under root 156.25
= 12.5 cm
CSA oc hemisphere=2×22/7×(3.5)^2
=77 cm^2
CSA of cone=22/7×3.5×12.5
=137.5 cm^2
TSA of toy=CSA of hemisphere+CSA of cone
=77+137.5
=214.5cm^2