Algebra for sewing?

This weekend I made a gift, and will show it off once it has been received.

THIS post is about Math.

In elementary school I did not like math, I was more interested in Art. (though I do remember getting a bad grade on an art project because I didn't follow the directions, it was too abstract for me, I wanted a more realistic finished project.)

Some of my friends will read that and wonder how this girl who is rather good at basic math and CAD could have disliked math at a young age?

Well this weekend I had to use Algebra, I don't remember much of high-school algebra and never took geometry. I have very basic math skills and can only remember Pi to 2 decimal places.

My problem was thus: I wanted to make a rectangle, where the shorter sides were 80% of the longer sides.

Then I had a known perimeter for three of those sides (2 short, 1 long.)

This is how I solved that problem

First I wrote it:
2(0.8X) + X = 14
But I found that to be too difficult for me with limited understanding of Algebra to solve

So I decided to switch the percentages instead of X being 80% of Y, Y was now 125% of X
(To prove my math is correct, simply divide 1 by 0.8 and you get 1.25.) So my new equation is:
2(1.25X) + X = 14

Multiply
2.5X + X = 14

Add
3.5X = 14

Divide both sides by 3.5

X = 4

Now put Sub 4 for X in the original equation to check work

2(1.25 * 4) + 4 = 14

Multiply inside parenthisies
2(5) + 4 = 14

Multiply
10 + 4 = 14

Add
14 = 14

And that was the start of my project, making the pattern with Algebra!

Yet more proof that you will use math in your life, despite what you may have told your school teachers.