Finding the Fourth Proportional to 1,385.56, 1,911.90 and 888.31

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.56 : 1,911.90 = 888.31 : x
2. Step 2: Convert to fraction form
   1,385.56/1,911.90 = 888.31/x
3. Step 3: Cross multiply
   1,385.56x = 1,911.90 × 888.31
4. Step 4: Simplify right side
   1,385.56x = 1,698,359.89
5. Step 5: Solve for x
   x = 1,698,359.89/1,385.56
6. Step 6: Final answer
   x = 1,225.76