Finding the Fourth Proportional to 1,385.64, 1,911.32 and 825.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.64 : 1,911.32 = 825.72 : x
2. Step 2: Convert to fraction form
   1,385.64/1,911.32 = 825.72/x
3. Step 3: Cross multiply
   1,385.64x = 1,911.32 × 825.72
4. Step 4: Simplify right side
   1,385.64x = 1,578,215.15
5. Step 5: Solve for x
   x = 1,578,215.15/1,385.64
6. Step 6: Final answer
   x = 1,138.98