More Maths - Multiple Square Metre Measurements

I asked ages ago how to get the square metre amount for patches on horse rugs & that's fine. I can do that easily.

However, I do lots of patches on one rug & have two different ways of finding out the total & get two different answers!

I have the following patch measurements in centimetres. Should I add all the lengths together then all the widths together & multiply the answers, or should I do a L x W sum for each & add the answers together?

29.5 x 12, 17 x 14, 39.5 x 13, 28 x 22.5, 24 x 20.

I got 1.1247m one way & 0.1753m the other way.

Help! Thanks.

Multiply all the patches seperately and then add the individual areas together. For those five rectangles the total area is 0.22155 m2

"a L x W sum for each & add the answers together?" - this!
I get 0.22155 sq metres.

Great, thanks. Got the same answer too, now.

I won't even ask why there's a different answer for each method!

Thanks again.

I can't for the life of me see why you are multiplying in metres.

29.5 x 12

???
29 metres of material is enough to build several completely new covers! You should convert all measurements to mm to work out the quantity of material you need. It is then a simple matter of shifting the decimal point to change the end result to metres in length if that is the only way you can buy patch material, otherwise leave it in mm or if you must, cm.

Here is a quick diagram that shows why the order matters in maths.

Attached files Order.pdf (6.1 KB) 

Stikkibeek;482343 wrote: I can't for the life of me see why you are multiplying in metres. ???
29 metres of material is enough to build several completely new covers!

She said her measurements were in cm., Stikkibeek.

12 x 6 = 18? I don't think so, but then I'm the one who had to ask the question in the first place!

Another thing to be aware of is wastage. Best bet is to (either electronically in a spreadsheet, or manually with graph paper) mark out the width, and each piece needed all to accurate scale across the width of the product you're purchasing and then get the total length required in a meter format.

Regardless of material or cost process, it still matters from afinancial cost perspective.

John

This is not about purchasing. This is about charging the customer for the amounts used.

The purchasing side of it is well taken care of. I am not buying the canvas for each job. I have a very good supply on hand the whole time.

Thanks very much.