Answer:
See below and attached.
Step-by-step explanation:
Draw a rectangle.
Divide it in half.
Divide each part in half again.
Lastly, divide each part again in half.
This will give a total of 8 sections.
Project a uses 1/2 of the fabric. This means it will use 4 out of the 8 pieces.
Project b uses 1/4 of the fabric. This means it will use 2 out of 8 pieces.
So the fabric that is left is 1 - 1/2 - 1/4 = 1/4.
You can find the amount left for any number of yards of fabric by taking f(x) = x/8 - 3/4