Answer:1/5 of the weight of the loaf of bread is protein.
Explanation:The fraction of the weight that is protein can be calculated by multiplying the fraction of the weight from the flour (9/10) by the fraction of the weight that is protein (2/9).
To do this, we multiply the numerators (2 x 9) to get the numerator of the final fraction and multiply the denominators (10 x 1) to get the denominator of the final fraction.
2/9 x 9/10 = (2 x 9) / (9 x 10) = 18/90
Now, we simplify the fraction by dividing the numerator and denominator by their greatest common factor, which is 18.
18/90 ÷ 18/18 = 1/5
Therefore, 1/5 of the weight of the loaf of bread is protein.