Finding the Fourth Proportional to 1,378.31, 1,902.72 and 788.73

Step by Step Solution

1. Step 1: Write the proportion equation
   1,378.31 : 1,902.72 = 788.73 : x
2. Step 2: Convert to fraction form
   1,378.31/1,902.72 = 788.73/x
3. Step 3: Cross multiply
   1,378.31x = 1,902.72 × 788.73
4. Step 4: Simplify right side
   1,378.31x = 1,500,732.35
5. Step 5: Solve for x
   x = 1,500,732.35/1,378.31
6. Step 6: Final answer
   x = 1,088.82