Finding the Fourth Proportional to 1,385.42, 1,912.06 and 825.90

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.42 : 1,912.06 = 825.90 : x
2. Step 2: Convert to fraction form
   1,385.42/1,912.06 = 825.90/x
3. Step 3: Cross multiply
   1,385.42x = 1,912.06 × 825.90
4. Step 4: Simplify right side
   1,385.42x = 1,579,159.57
5. Step 5: Solve for x
   x = 1,579,159.57/1,385.42
6. Step 6: Final answer
   x = 1,139.84