The flask consist of a cylindrical part and a frustum of a cone. The diameter of the base is 10 cm the diameter is 2 cm while that of neck is 2 cm. The vertical height of the flask is 12 cm.

Question

(a) the slant height of the frustum part;
(b) the slant height of the smaller cone that was cut off to make the frustum part.
(c) the external surface area of the flask. (Take pi = 3.142)

total height = 12
height = 10

Cylindrical part height = 12 - 2
cylindrical radius = 1

Answer 1

over and over

you ever gonna provide any input? I already suggested that you consider the top part of the cone that was cut off. Subtract that from the total cone, and you have the data for the frustrum.

Answer 2

If the frustrum's height is 2, and its base has diameter 10, and the top has diameter 2, then using similar triangles, you can see that the height of the missing part has height 1/2. So, the slant height of the frustrum is 4/5 of the total slant height of (5/2)√5.