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School math question. Your input?

Posted on 03/10/2015 5:48:37 PM PDT by MNDude

My daughter has this problem-solving question for her homework. I'm feeling kind of dumb on this one. What do you think is the correct answer?

Mrs. Feltner wants to put a border on a baby blanket. The area of the blanket is 12 square units. Which shows how many units of materials she needs for the border?

A 12 units B 14 units C 15 units D 21 units


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To: MNDude

It’s a quilting “B”


61 posted on 03/10/2015 6:29:40 PM PDT by ThomasThomas (EGO venit lego tantum titulus Posteri)
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To: MNDude

According to Common Core, first you have to make friends with the ten in the twelve. Then you have to add another friend to make twenty. From the twenty, you have to add the one and the two from the twelve to make twenty-three. Now, two plus three is five, which you add to the original twelve to get seventeen. But since you added three numbers together, you take back three from seventeen to get fourteen, and there’s your answer: B.


62 posted on 03/10/2015 6:29:41 PM PDT by Talisker (One who commands, must obey.)
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To: MNDude

14 units

It is 12 square units, therefore, 3units up top, 3 units on the bottom, 4 units to the left, and 4 units to the right.

Does the diagram below help?

[-—]
[ ]
] ]
[-—]


63 posted on 03/10/2015 6:30:56 PM PDT by GaltTrader
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To: kalt

Good point!


64 posted on 03/10/2015 6:31:55 PM PDT by GaltTrader
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To: MNDude
If it was shaped like this the perimeter would be 18.

65 posted on 03/10/2015 6:32:11 PM PDT by Clint N. Suhks (Bibi is the President we wish we had.)
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To: MNDude

Assuming whole units and a rectangular shape it must be an even number, and therefore B is the only available choice.

What grade is this for?


66 posted on 03/10/2015 6:33:14 PM PDT by BlueNgold (Have we crossed the line from Govt. in righteous fear of the People - to a People in fear of Govt??)
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To: MNDude

Insufficient information. This is just the kind of problem that a teacher with no grounding in math will give to a student, then look in the key to answer.


67 posted on 03/10/2015 6:33:51 PM PDT by Half Vast Conspiracy (!)
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To: Talisker

https://www.youtube.com/watch?v=UIKGV2cTgqA


68 posted on 03/10/2015 6:34:08 PM PDT by jjotto ("Ya could look it up!")
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To: Thurifer the Censer
3 x 4 would be 14, 2 x 6 would be 16, and 1 x 12 would be 26.

There are an infinite number of answers. It's a system of 2 equations in 3 unknowns. The answer that minimizes is 13.86 (approximately), which occurs for a square.

69 posted on 03/10/2015 6:35:13 PM PDT by FredZarguna (O, Reason not the need.)
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To: Attention Surplus Disorder

First thing I did was assume a rectangle and digest the square roots to define the lower limit. C and D could be acieved, but not using whole units.


70 posted on 03/10/2015 6:35:37 PM PDT by BlueNgold (Have we crossed the line from Govt. in righteous fear of the People - to a People in fear of Govt??)
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To: MNDude

We do not know the width of the border. Only its length. therefore, one cannot determine how many units are needed at the corners to meet the border corners. Suppose the border is 2X Units in width and the blanket 3x4 units. The border would have to be 3 units on two sides and 8 units on two sides to have the corners meet.


71 posted on 03/10/2015 6:35:39 PM PDT by anton
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To: MNDude

Answer is 14 units.

Area is 12 Square

4+4+3+3

or

6+6+2+2 = 16 Since that’s not one of the choices. you’re left with 14.


72 posted on 03/10/2015 6:37:36 PM PDT by Ouderkirk (To the left, everything must evidence that this or that strand of leftist theory is true)
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To: Half Vast Conspiracy

I’m a reading specialist. One year they assigned me as a co-teacher in a 6th grade math class. It didn’t last because I kept analyzing the story problems and coming up with the wrong answers....I swear this is true!


73 posted on 03/10/2015 6:37:54 PM PDT by chalkfarmer
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To: Jonty30
...10 units needing covering

What?

74 posted on 03/10/2015 6:38:16 PM PDT by Half Vast Conspiracy (!)
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To: MNDude

W=WIDTH, L=LENGTH


L*W = 12
and
2(L + W) = x (where x is one of the four possible values)
solve first eq for W...
W = 12/L
substitute in second giving
2L + 24/L = x
divide by 2...
L + 12/L = x/2
multiply both sides by L and rearrange...
L^2 - (x/2)L + 12 = 0
substituting each value (12,14,15,21) into this eq yields a quadratic that can be solved.
Answer “A” has no real roots, but B,C, and D all have nondegenerate real roots, therefore B,C or D are valid answers, but not A.


75 posted on 03/10/2015 6:38:35 PM PDT by SpaceBar
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To: RetiredTexasVet

15 works too.

L= 5.186
W+ 2.314


76 posted on 03/10/2015 6:38:50 PM PDT by lkco
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To: eastforker

Not true. 15 works also (L= 5.186, W=2.314)


77 posted on 03/10/2015 6:39:43 PM PDT by lkco
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To: Attention Surplus Disorder
However, The State wants you to answer 14 feet.

We've got a winner!

78 posted on 03/10/2015 6:39:43 PM PDT by Half Vast Conspiracy (!)
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To: Clint N. Suhks
πab is the area if it's an ellipse, but the perimeter is an elliptic integral, not solvable in closed form. The power series is


79 posted on 03/10/2015 6:40:58 PM PDT by FredZarguna (O, Reason not the need.)
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To: SpaceBar
nondegenerate positive real roots
80 posted on 03/10/2015 6:41:06 PM PDT by SpaceBar
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