Calculating Pounds Per Square Foot

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Here is what I tried, but the outcome seems really high.

seems high? doubling the size will be 162 and 2.4 each.

>>1147930
It's right
Drawing it would make the result seem more reasonable.

>>1147927
>>1147930
I suck at math but I think you first find what percentage 9x9 is of 12x12.

I think it's 56%

You then multiply 1.2 x 56%. That gives you .67

Add .67 to 1.2 and you get 1.87 lbs. approximately for a 12 x 12.

>>1147937
Correction it's 75%. That would give you .9 to 1.2. 2.1 lbs per 12x12

Basically what you're doing with cross multiplying...
weightPerSquareInch = 1.2 / 81
weightPerSquarFoot = weightPerSquareInch *144
=(1.2 / 81) * 144
=2.13333333

>>1147935
>>1147936
>>1147937
>>1147938
>>1147940
Thanks anons. That really tricks the eye.

I forgot WTF cross multiplying means, but just do it as ratios:

1.2lb / 81 in^2 = ?? / 144 in^2
(1.2lb / 81 in^2) * 144 in^2 = ??
?? = 2.13 lb

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>tfw using metric

>>1147927
>weight of 9inch by 9inch = X
> weight of 12" x 12" = Y

>>1148361
this is correct

9x9=81 (converting to number of sq. in. in sample)
If sample was 4x7 it would be 28
12x12=144 (converting to sq. in. per sq. ft.)

X/81=Z
Zx144=Y

IE: 9x9 weighs 13oz
Z=0.1604933827oz
Z*144=23.11111 oz

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>>1147927
1.2lbs/(9inch*9inch) in lbs/sqft

>>1147930
yep its right

>there's an entire thread devoted to calculating pressure

This board is retarded