first off let's convert the mixed fractions to improper fractions.

she already did half a hat, so we can say 
so she only needs enough fabric to make 3 more full hats, we know each one uses 9/7 ft, so

so you are going to use the Pythagorean theorem on the smaller triangle to find the connecting side's length

now you can find the bigger triangle's hypotenuse

c=4
(-y + 5a - 4) + (3y - a - 5) is simplified to 2y + 4a - 11
Answer:
i cannot say that i am perfect or good in math but if there is any problem then i will try to solve.
Step-by-step explanation: