The figure in the picture is made up of squares. Find the side of the bottom left square, if the side of the smallest square is 1.

3

Step-by-step explanation:

1x/1 x 3/1 = 3

1 unit x 3 = 3

Scale factor of larger square = 3

Ratio = 1 : 3

To determine the scale factor we use the larger measure and divide the compared smaller shape same side measure.

It doesn't matter if the shape or other sides are smaller or the same we take the larger side measure and compare it to the smaller shape.

Triangles for example

We have one smaller triangle 8 and 6

We show in workings shape is 8/6 = 12/x

Then to work out that smaller side we show 8x = 6 x 12 = 72

Then divide each within the sum by 8

8x/8 x 72/8 = 9

x= 9

We apply this to the square

1x/1 x 3/1 = 3

x=3