Finding the Fourth Proportional to 1,390.52, 2,085.82 and 688.34

Step by Step Solution

1. Step 1: Write the proportion equation
   1,390.52 : 2,085.82 = 688.34 : x
2. Step 2: Convert to fraction form
   1,390.52/2,085.82 = 688.34/x
3. Step 3: Cross multiply
   1,390.52x = 2,085.82 × 688.34
4. Step 4: Simplify right side
   1,390.52x = 1,435,753.34
5. Step 5: Solve for x
   x = 1,435,753.34/1,390.52
6. Step 6: Final answer
   x = 1,032.53