Saturday, March 31, 2012

March 29: How do we find the surface area and lateral area of pyramids & cones? (AIM)

Aim: How do we find the surface area and lateral area of pyramids & cones?



  • So like last time's review, the surface area is the outside of a solid. So here we'll be working with solids like pyramids & cones. The similarity between these two solids is that they both have triangle(s). 

  • Pyramids have triangles as the lateral area and only one face. This face can be any shape, from a circle (cone) to a heptagon (7 sides). 

  • A pyramid in general is a solid that connects a polygon base to a point, called the apex. 


  • For the surface area & lateral area this is the formula. 



  • But remember this is only for a square pyramid. For any base use the formula of 1/2pl (perimeter x slant length)  + B (area of the base). 

  • For a cone it's the same, but its for a circular base. 





  • Well that's about it. So try this problem !


What is the total surface area of this cone, rounded to 
the nearest tenth ?





Sources Cited: 

  1. John Schnatterly AKA -->  http://johnschnatterly.blogspot.com/
  2. http://www.mathsisfun.com/geometry/pyramids.html
  3. http://www.mrlarkins.com/geometry/InteractiveTextbook/Ch10/10EM/PH_Geom_ch10_Review.html
  4. http://hotmath.com/help/gt/genericprealg/section_9_5.html

1 comment:

  1. this is great but, where is the actual surface area formula for a cone?

    ReplyDelete