Finding the Fourth Proportional to 1,489.69, 2,055.67 and 900.55

Step by Step Solution

1. Step 1: Write the proportion equation
   1,489.69 : 2,055.67 = 900.55 : x
2. Step 2: Convert to fraction form
   1,489.69/2,055.67 = 900.55/x
3. Step 3: Cross multiply
   1,489.69x = 2,055.67 × 900.55
4. Step 4: Simplify right side
   1,489.69x = 1,851,233.62
5. Step 5: Solve for x
   x = 1,851,233.62/1,489.69
6. Step 6: Final answer
   x = 1,242.70