When writing a repeating decimal as a fraction, why does the fraction have only 9a or 9s and 0s as digits in the denominator?

If anyone has done the algebra 2 chaos theory portfolio would you be wiling to me? i kind of know what i'm doing i just don't know if i'm doing it right.

Question 101 points)which equation in slope-intercept form represents the line that passes through (5, 1) and(-4,7)

Find the perimeter of the figure shown above. a. 40 cm c. 52 cm b. 60 cm d. 75 cm select the best answer from the choices provided