Posted by alex on Monday, October 5, 2009 at 4:33pm.
faye has 20 feet of fencing to make a rectangular pen for her dog.What is the largest area she can fence in?
- math - alex, Monday, October 5, 2009 at 4:34pm
- math - alex, Monday, October 5, 2009 at 4:38pm
is that right im just gessing
- math - Ms. Sue, Monday, October 5, 2009 at 4:39pm
Let's see --
it could be 5 + 5 + 5 + 5
or 4 + 4 + 6 + 6
or 3 + 3 + 7 + 7
Find the areas of these pens.
A = length times width
So -- a 3 foot by 7 foot pen would be 21 square feet.
Find the areas of the other two pens. Which gives you the most square feet?
- math - MathMate, Monday, October 5, 2009 at 4:39pm
For a math question:
Make a table of width (W) and lengths (L) that add up to 20 for perimeter = 2(W+L).
Calculate the area for each line. Choose the biggest area.
Width Length Area
1 9 9
2 8 16
3 7 21
4 6 24
8 2 16
9 1 9
For a calculus question:
Let W=width, then
For maximum or minimum:
dA/dW=10-2W=0, or W=5
d²A/dW²=-2 <0 so maximum.
A(5)=5(10-5)=25 (maximum area)
- math - alex, Monday, October 5, 2009 at 5:15pm
hi im only in 4th grade so i really kind of need simple answers
- math - Ms. Sue, Monday, October 5, 2009 at 5:27pm
Please see my answer. I'm sure you can figure out your answer using that information.
- math - alex, Monday, October 5, 2009 at 5:28pm
thanks ms.sue u rock
- math - Ms. Sue, Monday, October 5, 2009 at 5:30pm
You're welcome, Alex. :-)
Answer This Question
More Related Questions
- Math - Laura has 20 feet of fencing to make a rectangular pen for her dog. What ...
- math - A rectangular dog pen that has the greatest possible area within a budget...
- grade (5) math - Design a rectangular dog pen that has the greatest possible ...
- Math - Brenda is building a rectangular pen for her dog. She has enough fencing ...
- Math - Can you please help me figure out what to do? ... here is the question...
- Math - You are designing a rectangular dog pen off the back of your house. The...
- Math - 1. A gardener has 140 feet of fencing to fence in a rectangular vegetable...
- math - A farmer will make a rectangular pen with 100 feet of fence using pasrt ...
- Pre-Calc - A farmer is making a pig pen next to the barn. He has enough ...
- math - a farmer has enough fencing to build 40 feet of fence. He wishes to build...