FOR GMS ICSE 2014 3rd Sept

Ch : 22 : Cone

Today, we work with the cone ! We will also be finding the volume of ice cream you may be able to fill it with !

Please look at pg324 in your text books. Look at the diagram of a cone at the end of the page. Please note that when discuss in the cone shape, we use the following letters :

• r : radius of the circular portion of the cone.
• h : the perpendicular height of the cone.
• l : the slope of the cone (from the vertex to the base), this is also called the slant height

As we have done with the Cylinder, we shall also be finding the curved surface area, the total surface area and the volume of the cone. You thus need to remember the following formulas :

• curved surface area : πrl
• total surface area = curved surface area + area of circular section : πrl + πr² = πr(l + r)
• volume = ⅓ πr²h

With the above information, please work out : Ex.22 (B) : Nos.1, 2, 3, 11, 12

Please learn your tables and be careful with your working. Draw a diagram for each sum. Be neat in your work - work conscientiously to be neat.

All the best !