SOLUTION: The Giant Causeway in Northern Ireland is a mass of basalt prism-shaped columns packed tightly together... Most of the prisms are hexagonal. The average height of a column is about

Algebra ->  Surface-area -> SOLUTION: The Giant Causeway in Northern Ireland is a mass of basalt prism-shaped columns packed tightly together... Most of the prisms are hexagonal. The average height of a column is about      Log On


   

Question 956509: The Giant Causeway in Northern Ireland is a mass of basalt prism-shaped columns packed tightly together... Most of the prisms are hexagonal. The average height of a column is about 14 m. The average diameter of the columns is 45cm. Assuming that the average column is a regular prism, find the surface area of an average column of the Giant's Causeway. (I put the "..." to show that stuff was included, but it's unnecessary info because it's talking about how they were formed and not talking about shapes or anything) I'm not sure how to even start this problem because it's saying hexagonal prism and then stating the diameter, I'm not sure what to do with that. Thank you!!!!!!
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
The edge, a, of a hexagon=1/2 the diameter=0.225m; h=height=14m
The area of a hexagonal column=sum of its faces=6ah=6(0.225m)(14m)=18.9 sq m
and the area of its top:
%283sqrt%283%29%2F2%29a%5E2=%283sqrt%283%29%2F2%29%280.225%5E2%29=0.132m%5E2
So surface area of an average column is 18.9 sq m+0.132 sq m=19.032 square meters.