bearisgray

You could piece the strips you have together - and then cut the pieced strips together into 2.25 x 7 inch units .

If you sew two 1.5 strips together - you end up with a 2.5 inch strip - if you trim it down to 2.25 - you are losing very little. The extra seam might add some interesting texture.

(I THINK that's what ckcowl is suggesting?)

OR

Do you want to reduce the size of the components both lengthwise and crosswise?

Let's assume that you use your 1.5 inch strips for this.

Your finished width will be 4/7 of the pattern size. (1.5 - 0.5) / (2.25 - 0.5)
(1 inch instead of 1.75 inches)

So then one would take the same fraction and multiply the finished length by that fraction.

4/7 x 6.5 = 3.714 finished size

You will need to add 0.5 inch back to that for seam allowances which would be 4.214 inches.

Most of us don't have those marks on our rulers.

You could try experimenting with pieces cut 1.5 x 4.25 and see if you can get the look you want.

Are ALL the pieces cut 2.25 x 7 inches? 1.75 x 6.5 ends up being an uncommon ratio for a unit (7:26)