Answer:
r = 200
Step-by-step explanation:
[tex]Area of sector = (\frac{225}{360})[/tex]×πr² = [tex](\frac{5}{8})[/tex] ×πr²
[tex](\frac{5}{8})[/tex] ×πr² = 250π
[tex](\frac{5}{8})[/tex] ×r² = 250
r² = [tex](\frac{8}{5})[/tex] × 250
r² = 400
r = 200 (r is a length so, it's positive)