Finding the Fourth Proportional to 1,385.01, 1,911.20 and 825.57

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.01 : 1,911.20 = 825.57 : x
2. Step 2: Convert to fraction form
   1,385.01/1,911.20 = 825.57/x
3. Step 3: Cross multiply
   1,385.01x = 1,911.20 × 825.57
4. Step 4: Simplify right side
   1,385.01x = 1,577,825.26
5. Step 5: Solve for x
   x = 1,577,825.26/1,385.01
6. Step 6: Final answer
   x = 1,139.22