Answer: r = 5
Steps:
[tex]a_n=ar^{n-1}[/tex]
1. add Values to formula
[tex]1250=2r^{5-1}[/tex]
2. get r alone
[tex]\frac{1250}{2}=\frac{2r^{4}}{2}[/tex] ➜ [tex]625= r^4[/tex]
3. get rid of the exponents
[tex]\sqrt[4]{625}= \sqrt[4]{r^4}[/tex] ➜ [tex]\sqrt[4]{625}= r=5[/tex]
r = 5
