Question 1061035: Mr.Javier designed an arch made of bent iron for the top of a school's main entrance.The 12 segments between the two concentric semicircles are each 0.8meter long.Suppose the diameter of the inner semicircle is 4 meters.What is the total length of the bent iron used to make this arch?
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! There is an inner semicircle with diameter 4 meters,
an outer semicircle with diameter 5.6 meters (0.8+4+0.8=5.6),
and  straight pieces, each  meters long, connecting the two semicircles.
The circumference of a circle can be calculated as  ,
so the length of each semicircle will be  .
The lengths (in meters) of iron needed for each part of the arch are
inner semicircle:  ,
outer semicircle:  ,
straight connecting pieces:  .
The total length is the sum of those lengths.
Rounded to the nearest  meter, the length needed would be  .
I would buy 25 meters, since some metal may be wasted in the cutting process,
and the supplier would probably laugh if I ask for a more precisely specified amount.
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