A cone has a height of 12 cm12cm and its base has a radius of 15 cm15cm. If the cone is horizontally cut into two segments 3 cm3cm from the base, what would the surface area of the bottom segment be?

1 Answer
Jan 2, 2017

Total surface area of bottom segment is 1500.5(1dp)1500.5(1dp) sq.cm

Explanation:

The cone is cut at 3 cm from base, So upper radius of the frustum of cone is r_2=(12-3)/12*15=11.25r2=1231215=11.25cm ; slant ht l=sqrt(3^2+(15-11.25)^2)=sqrt(9+14.0625)=sqrt 23.0625=4.80l=32+(1511.25)2=9+14.0625=23.0625=4.80cm

Top surface area A_t=pi*11.25^2=397.61At=π11.252=397.61 sq.cm
Bottom surface area A_b=pi*15^2=706.858Ab=π152=706.858 sq.cm
Slant Area A_s=pi*l*(r_1+r_2)=pi*4.80*(15+11.25)=396.03As=πl(r1+r2)=π4.80(15+11.25)=396.03 sq.cm

Total surface area of bottom segment =A_t+A_b+A_s=397.61+706.86+396.03=1500.5(1dp)=At+Ab+As=397.61+706.86+396.03=1500.5(1dp)sq.cm[Ans]