Finding the Fourth Proportional to 1,385.52, 1,911.60 and 861.12

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.52 : 1,911.60 = 861.12 : x
2. Step 2: Convert to fraction form
   1,385.52/1,911.60 = 861.12/x
3. Step 3: Cross multiply
   1,385.52x = 1,911.60 × 861.12
4. Step 4: Simplify right side
   1,385.52x = 1,646,116.99
5. Step 5: Solve for x
   x = 1,646,116.99/1,385.52
6. Step 6: Final answer
   x = 1,188.09