SOLUTION: A circular plot of ground is to be enclosed with posts. If the posts are placed a ft. apart, the amount needed will be 150 short. If placed 1 yard apart, the amount will be 70 ov

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Question 1058002: A circular plot of ground is to be enclosed with posts. If the posts are placed a ft. apart, the amount needed will be 150 short. If placed 1 yard apart, the amount will be 70 over. Determine circumference of plot.

Circumference of circle = pi * diameter.
Unsure how to proceed. Thanks.


Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
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A circular plot of ground is to be enclosed with posts. If the posts are placed a ft. apart, the amount needed will be 150 short.
If placed 1 yard apart, the amount will be 70 over. Determine circumference of plot.
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Let x be the circumference length, in feet.

The condition "If the posts are placed a ft. apart, the amount needed will be 150 short" means

x = n + 150,   (1)

where "n" is the number of posts stocked at the site.

The condition "If placed 1 yard apart, the amount of posts will be 70 over." means 

x/3 = n - 70.   (2)    ( 1 yard == 3 ft )

From (1), express n = x-150 and substitute it into (2) replacing n. You will get

x/3 = x - 150 - 70,   or

2x/3 = 220.

Then x = %28220%2A3%29%2F2 = 330.

Answer.  The circumference is 330 ft.
         The number of posts stocked at the site, is 330-150 = 180.