







Two cones 
20140409 

c.j pose la question : what is the length of the radius of the LARGER cone(the LARGER cone has a slant height of 15) when the SMALLER cone has a radius of 8 and a slant height of 12ft ,please help. Penny Nom lui répond. 





Cones, pyramids, cylinders and prisms 
20120913 

Roy pose la question : I read on this page that a pyramid is a special kind of cone, but a cone is not a pyramid. Does this apply to cylinders. Is a prism a special kind of cylinder, but a cylinder is not a prism? Robert Dawson lui répond. 





Two conical tanks 
20110217 

rustom pose la question : Two vertical conical tanks (both inverted) have their vertices connected by a short horizontal pipe.
One tank, initially full of water, has an altitude of 6 ft. and a diameter of base 7 ft.
The other tank, initially empty, has an altitude of 9 ft., and a diameter of base 8 ft.
If the water is allowed to flow through the connecting pipe, find the level to which
the water will ultimately rise in the empty tank (Neglect the water in the pipe.) Penny Nom lui répond. 





Two cones 
20061230 

Cassie pose la question : A cone of radius 6 and height 12 and a different cone of radius 8 and height 12 intersect as shown in the figure below, where the vertex of one matches with the center of the base of the other. Find the volume of the intersection of the two cones (in exact form). Penny Nom lui répond. 





How fast is the water level rising 
20060812 

Erin pose la question : Water runs into a conical tank at the rate of 9ft^{3}/min. The tank stands point down and has a height of 10 ft. and a base radius of 5 ft. How fast is the water level rising when the water is 6 ft. deep? (V=1/3 pi r^{2} h). Penny Nom lui répond. 





Pyramids and cones 
20060606 

Melissa pose la question : I was wondering if a cone can be considered a pyramid. Looking at many definitions of pyramids I have read that pyramids come to a common vertex. A cone comes to a vertex. But I also read that pyramids all have triangular faces. In this case a cone would not be considered a pyramid. Am I correct? Chris Fisher lui répond. 





Surface areas 
20050511 

Jessica pose la question : How can I demonstrate to my high school students the reason for the formulas for the surface area of a prism, right cylinder, and regular pyramid, and right cone? Penny Nom lui répond. 





Making a cone 
20031222 

Tracie pose la question :
I am working on a craft project at home and I have been given the following information: 16" tall and 13" diameter at base, with 1 and 1/2 " opening at top.
Is there a basic formula for creating a cone with this info?
Claude Tardif and Penny Nom lui répond. 





A sphere inscribed in a cone 
20030810 

A student pose la question : A sphere with radius 5cm is inscribed in a right circular cone 20 cm in height.find
(a) the base radius ,volume of the cone (b)volume of the shaded space( to 3 sig fig) Penny Nom lui répond. 





The vertex of a cone 
20030327 

Holly pose la question : I read your response to Callie about whether a cone has a vertex or not. Is it ONLY a vertex if both halves of the cone are together or can one half of the illustration have a vertex? Walter Whiteley lui répond. 





A paper model of a cone 
20020814 

Bruce pose la question : I have made a paper model of a cone, cut a sloping section, and removed the top. I have drawn the major and minor axis on the paper surface of the section. The major axis is not symmetrical about the minor axis. To me, this is not an ellipse. To me, an ellipse is a tubular section, because this gives a symmetrical major axis. What is your opinion? Walter Whiteley and Chris Fisher lui répond. 





Conics 
20020529 

Brooke pose la question : Which conic cannot be generated by an intersection of a plane and a double napped cone? Chris Fisher lui répond. 

