Finding the Fourth Proportional to 1,013.83, 1,399.45 and 641.06

Step by Step Solution

1. Step 1: Write the proportion equation
   1,013.83 : 1,399.45 = 641.06 : x
2. Step 2: Convert to fraction form
   1,013.83/1,399.45 = 641.06/x
3. Step 3: Cross multiply
   1,013.83x = 1,399.45 × 641.06
4. Step 4: Simplify right side
   1,013.83x = 897,136.52
5. Step 5: Solve for x
   x = 897,136.52/1,013.83
6. Step 6: Final answer
   x = 884.90