Calculate the Percentage of 4.5 Over 90: Conversion Challenge

To solve the problem of calculating what percentage 4.5 is of 90, we will employ the percentage formula:

Step 1: Identify the given numbers. We have $4.5$ as the part and $90$ as the whole.

Step 2: Apply the formula for percentage:\
\text{Percentage} = \left( \frac{\text{part}}{\text{whole}} \times 100 \right)\%

Step 3: Insert the given values into the formula:
\( \text{Percentage} = \left( \frac{4.5}{90} \times 100 \right)\%

Step 4: Calculate the fraction $\frac{4.5}{90}$:
$\frac{4.5}{90} = 0.05$

Step 5: Convert the fraction to a percentage by multiplying by 100:
$0.05 \times 100 = 5$

Therefore, 4.5 is 5% of 90, which corresponds to choice id="1".

Thus, the solution to the problem is that 4.5 over 90 as a percentage is 5%.