Skip to comments.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
Poorly worded question, but I think the answer is A.
I get 14 units.
Sorry, I reread the question and the answer is B.
There’s no way to know for sure without knowing the shape of the blanket. An area of 12 could be 4 by 3, for instance. Then the perimeter (which tells you the length of fabric you need for the border) would be 14. But it could also be 6 by 2 (perimeter 16) or round (perimeter about 12.27) or lots of other things.
if the blanket is 3x4 it would be 14, three for each of the shorter sides and 4 each for the longer sides. 2x6 and 1x12 would be the same
Ok, I get it now. thanks!
B....because I quilt.
That is not a math question, its a question for the lady at the fabric store.
2 border units for each of the 4 corner units, 1 border unit each for the other 8 units.
We only know that the area of the blanket is 12 square units. So the blanket could be 6x2, 3x4, 12x1, etc.
Each of those would have a different perimeter, and so would need a different amount of border material.
I get B (14) if the piece is 3x4.
I get 26 if it’s 1x12 and 16 if it’s 2x6.
That’s using the ol’ Perimeter = Length plus width x 2.
Why would 2x6 by the same? Wouldn’t it be 16 instead of 14? And 1x12 would be 26.
B. 3 + 3 + 4 + 4 = 14
Imagine a blanket 3’ x 4’. (12 Sq Ft)
The perimeter is (4 + 3) x 2.
Of course, one would want to allow an extra foot of ribbon to account for hemming, ease, and the mitered corners.
But only a person who sews or quilts would know that.
Substitute “feet” for “units”.
The blanket is 12 sq feet.
Could be 3’ x 4’, in which case 3 + 3 + 4 + 4 border = 14 feet.
Could be 6’ x 2’, in which case 6 + 6 + 2 + 2 = 16
Could be 12’ x 1’ in which case 12 + 12 + 1 + 1 = 26 feet.
Could be [sqrt] 12 x [sqrt] 12 = 3.464 x 3.464 in which case (4)(3.464) = 13.85.
Insufficient information to answer unless we assume the blanket is 3 x 4. However, The State wants you to answer 14 feet.
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