A cone has a height of 11 cm and its base has a radius of 5 cm. If the cone is horizontally cut into two segments 2 cm from the base, what would the surface area of the bottom segment be?

1 Answer
Jan 6, 2018

Total surface area of bottom segment is 193.86 sq.cm.

Explanation:

The cone is cut at 2 cm from base, So upper radius of the frustum

of cone is r_2=(11-2)/11*5~~4.09 cm . Slant height is

l=sqrt(2^2+(5-4.09)^2)=sqrt(4+0.83)=sqrt 4.83 ~~2.2 cm.

Top surface area A_t=pi*4.09^2~~52.57 sq.cm

Bottom surface area A_b=pi*5^2 ~~78.54 sq.cm

Slant Area A_s=pi*l*(r_1+r_2)=pi*2.2*(5+4.09)~~62.74

sq.cm. Total surface area of bottom segment is

A_t+A_b+A_s=52.57+78.54+62.74 ~~193.86 (2dp)

sq.cm [Ans]