Answer: 5:4
Step-by-step explanation:
If two shapes are similar , then
[tex]\frac{A_{1} }{A_{2}}= (\frac{r_{1}}{r_{2}}) ^{2}[/tex]
substituting the given ratio into the formula , we have :
[tex]\frac{25}{16}=(\frac{r_{1}}{r_{2}})^{2}[/tex]
take the square root of both sides
therefore:
[tex]\frac{r_{1}}{r_{2}}= \frac{5}{4}[/tex]
Therefore : the ratio of their radius = 5:4