Lateral surface area of a rt circular cone

[elkaydubya]

How do you calculate the lateral surface area of a right circular cone when the slant height is 8 inches and the apex/vertex is 40 degrees? The answer is 64/9 pi inches but I cannot figure out how to get there.

 

[wjm11]

calculate the lateral surface area of a right circular cone

http://math.about.com/od/formulas/ss/su ... avol_2.htm
http://math.about.com/library/blmeasurement.htm
https://pantherfile.uwm.edu/ericskey/ww ... ode15.html
http://www.analyzemath.com/Geometry_cal ... _cone.html
etc.

 

[JeffWest]

if you need information about the apex/vertex angle look at this web sight.

http://mathworld.wolfram.com/Cone.html

Good luck