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anonymous
 one year ago
If 400 feet of fencing is used to enclose a rectangular plot of land that borders a river, what is the maximum area that can be enclosed?
anonymous
 one year ago
If 400 feet of fencing is used to enclose a rectangular plot of land that borders a river, what is the maximum area that can be enclosed?

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anonymous
 one year ago
Best ResponseYou've already chosen the best response.0It's pretty east to start out. Use the formulas: A = w * h P = 2h + w where P is the perimeter of the fence (400 ft), h is the length of one of the 2 parallel sides, and w is the length of the side that is parallel to the river.

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay so 400 = 2h + w now what?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0system of equations?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so solve for either h or w in that equation and substitute that into the Area formula

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so 400 = 2h + (400  2h)

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so that w should be substituted into the Area formula: A = w * h so A = (400  2h) * h

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0and now just find the derivative and set if equal to 0?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0and yes. take the derivative, set to 0, and that will give you h. you can find w from that, which will give you the total area

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so then h = 100 right?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0is w just the x coordinate at x =100?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0i mean y coordinate?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0sure. if you're mapping w (ycoord) against h (xcoord).

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0okay so then my area would be 15000?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0dw:1438391127763:dw

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0see your whole fence is h + h + w = 400

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0you know h = 100, so w = 200

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0so A = w * h = 200 * 100 = 20000

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0a okay whoops i set the 100 as w instead of h

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0it happens. hope that helped.
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