Finding the Fourth Proportional to 1,137.92, 1,705.40 and 520.72

Step by Step Solution

1. Step 1: Write the proportion equation
   1,137.92 : 1,705.40 = 520.72 : x
2. Step 2: Convert to fraction form
   1,137.92/1,705.40 = 520.72/x
3. Step 3: Cross multiply
   1,137.92x = 1,705.40 × 520.72
4. Step 4: Simplify right side
   1,137.92x = 888,035.89
5. Step 5: Solve for x
   x = 888,035.89/1,137.92
6. Step 6: Final answer
   x = 780.40