8. \( \frac{5}{10}=\frac{}{90} \)

To solve the equation \( \frac{5}{10}=\frac{x}{90} \), we can cross-multiply for a quick solution. This gives us \( 5 \times 90 = 10 \times x \), resulting in \( 450 = 10x \). Dividing both sides by 10, we find \( x = 45 \). So, \( \frac{5}{10}=\frac{45}{90} \). You might have noticed that \( \frac{5}{10} \) simplifies to \( \frac{1}{2} \), while \( \frac{45}{90} \) also simplifies to \( \frac{1}{2} \). This is a neat demonstration of how equivalent fractions work! Whenever you see a ratio, you can often simplify it to a familiar form to easily compare or calculate.