To find the percentage change from 550 to 900, we need to first calculate the difference between the two numbers.

Step 1: Difference = Final Value - Initial Value

Difference = 900 - 550

Difference = 350

Step 2: Next, we need to find the absolute value of the difference. This is because percentage change is always calculated as a positive value.

Absolute Difference = |Difference|

Absolute Difference = |350|

Absolute Difference = 350

Step 3: Now, we can calculate the percentage change using the formula:

Percentage Change = (Absolute Difference / Initial Value) x 100

Percentage Change = (350 / 550) x 100

Percentage Change = 63.64%

Therefore, the percentage change from 550 to 900 is 63.64%. This means that there was an increase of 63.64% from 550 to 900.