convert 4.5 into a fraction

1. Write the decimal number as a fraction:
4.5 = \frac{4.5}{1}
2. Remove the decimal by multiplying the numerator and the denominator by 10 (since there is one digit after the decimal point):
\frac{4.5 \times 10}{1 \times 10} = \frac{45}{10}
3. Simplify the fraction by finding the greatest common divisor (GCD) of 45 and 10, which is 5:
\frac{45 \div 5}{10 \div 5} = \frac{9}{2}

Therefore, 4.5 = \frac{9}{2}.