Finding the Fourth Proportional to 1,384.68, 1,910.78 and 825.78

Step by Step Solution

1. Step 1: Write the proportion equation
   1,384.68 : 1,910.78 = 825.78 : x
2. Step 2: Convert to fraction form
   1,384.68/1,910.78 = 825.78/x
3. Step 3: Cross multiply
   1,384.68x = 1,910.78 × 825.78
4. Step 4: Simplify right side
   1,384.68x = 1,577,883.91
5. Step 5: Solve for x
   x = 1,577,883.91/1,384.68
6. Step 6: Final answer
   x = 1,139.53