Finding the Fourth Proportional to 1,385.04, 2,076.60 and 690.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,385.04 : 2,076.60 = 690.72 : x
2. Step 2: Convert to fraction form
   1,385.04/2,076.60 = 690.72/x
3. Step 3: Cross multiply
   1,385.04x = 2,076.60 × 690.72
4. Step 4: Simplify right side
   1,385.04x = 1,434,349.15
5. Step 5: Solve for x
   x = 1,434,349.15/1,385.04
6. Step 6: Final answer
   x = 1,035.60