Answer :
Given:
Radius of lower end “r” = = 1 cm
Radius of upper end “R” = = 2.5 cm
Height of frustum “H” = 6 cm
To find: The external surface area.
Formula Used:
CSA of frustum = π(R + r)L
CSA of hemisphere = 2πr2
Explanation:
Let “L“ be the slant height of the frustum,
L of frustum =
= 6.18 cm
External Surface Area = CSA of frustum + CSA of hemisphere
= π(R + r)L + 2πr2
= π [(2.5 + 1)6.18 + 2 (1)2] cm2
= [(3.5)6.18 + 2] cm2
= [ 21.63 + 2] cm2
= (23.63) cm2
= cm2
= 74.26 cm2
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